A Case of Illusion
by The Lady Of Purpletown
Summary: Sherlock is claiming John's common room again. John finally finds the courage to ask his best friend something that has been on his mind for some time. Could be dangerous... Especially when a gift arrives that means the start of a whole new adventure.
1. Christmas Exchange

_The first chapter of this story was originally a oneshot, written as a Christmas exchange gift for Endlesshorizons. A little over a year later, I have decided to return to this universe and continue the story. However, I didn't make any changes in this first chapter, so if you prefer to read short stories, this can still be read on its own._

 _Enjoy!_

* * *

"I _knew_ it," Sherlock said, shutting his folder with a snap that startled John enough that he made a blot on his parchment.

"What?" John asked, a little annoyed.

"The dragon smugglers." Sherlock gave an impatient flick with his wand so the Potions homework in John's lap looked more pristine than it had done before. "They have their base in Cardiff."

"Brilliant," John said, smiling a little at his own writing. "How do you know?"

"Oh, John, they have left traces _everywhere_."

Both the gleam in Sherlock's eyes and the fact that the investigation had been started by the Ministry three months earlier told John that that couldn't be entirely true, but he leaned in closer to see the file Sherlock was holding.

"I can't believe Mycroft didn't realise this," Sherlock continued, shaking his head. "I'd almost think they've paid him to shut up..."

"Yes, alright, Sherlock. Tell me what you've found out," John said with a fond eye roll.

"Look." Sherlock pulled an article out from the stack of newspaper clippings on the floor and tapped it with his wand, at which a tangle of lines appeared. He pointed at the centre of them. "This is where they are operating from. All the ends of the lines are the spots where dragon sightings are reported. Let's say that half of them were true –" He tapped the article again and half of the lines vanished, "– then it is still quite obvious."

John nodded. "So they didn't even bother to connect the dots?"

"I told you they're idiots at the Ministry," Sherlock shrugged. "But there is more." He discarded the article and picked another one from the stack, seemingly at random.

John stared at it blankly. "Er..."

"Can you believe their arrogance?" In his enthusiasm, Sherlock hopped from his spot on the floor onto the armrest of John's chair.

Instinctively, John shifted closer to his warmth, but the thin piece of paper didn't make him any wiser. "It's just a clipping. And you've marked four letters, but... I doubt 'HAHA' has to mean anything. So unless you think it's arrogant that they mucked up the grammar in the fifth sentence..."

"'HAHA' means _everything_ ," Sherlock said dramatically, taking another clipping. "Those are the first letters of the first word of every other sentence. Now look at this one."

He pushed it into John's hands; once again, it was about the dragon smugglers, and it was dated a few days after the first one. "'THEY'?" John read.

Sherlock nodded. "The writer is giving us a message. A very, very stupid one. Because a week later, she wrote her sentences so that if you knew where to look, you'd read "WILL". The second sentence starting with an 'L' was such a disaster that it caught my attention and that's why I had a closer look at all the others. Now guess what she did after that... 'NEVER', 'KNOW', 'ITWAS' and, in a very short one saying that the investigation still hasn't had any results: 'ME'."

"You're kidding," John said, his eyes wide.

"Nope. But our oh so brilliant reporter, Ms Kitty Riley, must be laughing up her sleeve. Her business is booming, they can't find any clues and she can even leave secret messages in the Daily Prophet. Let's see if she's still laughing when I've sent an Owl to Magical Law Enforcement." He swept his clippings back into the folder, put it aside and gave John an expectant look.

"Amazing," John said, heart-felt. "They would have been searching for ages without you."

Sherlock nodded. "Fools." He let himself slide off the armrest into the chair, where there actually wasn't room for him, but John shifted to allow it anyway. Not that there weren't enough chairs for both of them. Apart from a group of whispering third-years in the far corner – probably up to something illegal – the Hufflepuff common room was completely deserted. Most students had gone to bed, and not that many had stayed at Hogwarts for a start. Had Sherlock not been there, John would have spent the loneliest Christmas of his life, unable to face the chaos that called itself his home. He was the only sixth-years from Hufflepuff in the castle. But Sherlock _was_ here. In the wrong common room, as usual, because neither of them found the Slytherin common room very homely – and at the moment more or less in his lap. So it had become a very good Christmas holiday indeed.

And yet, John kept fretting about something. Not constantly, as Sherlock would drag him along throughout the day and John wouldn't really think at all if he was running after him, thinking up fibs to distract wandering teachers, or training his aim by covering Sherlock in snow (at the one occasion _he_ had managed to drag Sherlock along for a change). But at moments like this, when all was quiet and Sherlock had just done something clever and they had somehow ended up snuggling again... That was when his mind returned to the same question over and over, although he never dared to ask it. It was ridiculous, maybe even wrong, to want this so badly. He had even considered to ask it on Christmas Eve, instead of a gift, but that felt like he was not giving Sherlock a choice – and he would already have bought him something, anyway.

"John?"

John blinked and found that Sherlock was frowning at him. "Yes?"

"You're thinking very loudly." Sherlock gave him a searching look.

"Oh. Sorry." John blinked again. "You didn't actually hear what I was thinking, did you? I mean, that Legilimency thing Greg was talking about sounded pretty creepy..."

Sherlock rolled his eyes. "I don't need magic to see that you're worried about something. It's probably ridiculous."

John scowled, meanwhile wondering if Sherlock was right. They usually had no personal boundaries whatsoever. Sherlock _was_ in his lap. Was it ridiculous to think there was any difference from cuddling in a bed? To finally ask him to stay over and share warmth? Maybe Sherlock would just find it practical. Every night he had to walk the cold corridors back to his own common room, only to meet John again at breakfast and spend the rest of the day together. Actually, _that_ was sillier than asking him to stay. Then again, John couldn't just present the idea as a practicality, or Sherlock would ridicule it, saying that he wasn't afraid to be caught out at night by the teachers, as they couldn't possibly expel him with his marks – even though they must be wondering what he wanted to achieve with the set of subjects he had chosen after his OWLs.

On the other hand, John could hardly explain to Sherlock how much it would mean to have him close when he was asleep. If he admitted that... He couldn't lose Sherlock's friendship by disgusting him. He simply couldn't.

And just like that, he was all the way back to the start of his inner conflict.

Sherlock sighed. "You might as well tell me about it."

"I... Fine," John heard himself saying, to his own surprise. At some point, he should probably learn not to give in to Sherlock's every wish, but perhaps now wasn't the time to start. "I was just wondering. I mean..."

"Do try to finish your sentence before I've fallen asleep." Sherlock snuggled into John's shoulder, which helped.

"Yes. You're sleepy. That's good," John babbled, before realising he was rather showing his hand there.

Sherlock lifted his head to give him a look.

"There's no one in my dormitory," John said quickly, squirming under Sherlock's scrutiny. He decided that putting his now forgotten Potions homework neatly on the table in front of him was a good way to avoid Sherlock's gaze, even if it was a little awkward to move forward while Sherlock was still leaning on him.

"Of course there's no one there," Sherlock said, sounding puzzled. "You are here. Was this supposed to give me some clue?"

" _Yes_." Trust Sherlock to exasperate him enough that he _would_ look at him. "I'd like you to stay. But... But you don't have to. I mean, only if you want to. It's fine if you don't. Really."

"What's _wrong_ with you tonight?" Sherlock asked, and John cringed. He shouldn't have asked. It was a mistake and he would regret it for the rest of his life, and really, he should have known, there was a reason why he had hesitated for so long, he should have listened to himself...

"I don't mind staying here," Sherlock said with a shrug. "I don't know why that was so hard to ask. You don't have any bad sleeping habits or problems that I should know about – except for the occasional nightmare, but I'm sure I can handle that."

"I'm not talking about you sleeping in one of the other beds," John said, very quietly and in one breath.

"Don't be boring."

"Right. But the beds are small."

"So is this chair," Sherlock pointed out, pushing John back in place to reclaim his shoulder-pillow.

"People might talk," John said quietly.

"People do little else," Sherlock shrugged. "Besides, it was your idea."

"Yes. I don't mind. It's just that perhaps you didn't like them thinking..."

"I'm hardly going to discourage them the one time they think at all, John," Sherlock said, sounding exasperated.

"Oh." John wondered if that was supposed to make him feel smug. Because it did, a little. "So... Can we move?"

Sherlock groaned, but then sat up and gave John's shoulder a remorseful look. "I guess it's better for you if we don't fall asleep here."

"Much better," John nodded, without really thinking of his old Quidditch injury.

As he was being brave tonight, he decided that he could as well hold Sherlock's hand all the way to the dormitory after Sherlock had pulled him to his feet. One of the third-years let out a high-pitched giggle when they passed them, which John wouldn't have paid much attention to if her friend hadn't very loudly whispered: "Quiet, Tessa!". Blushing, he crossed the room a little faster and then pulled the round door shut behind them.

There, he spent a moment feeling awkward, but that was solved very quickly by Sherlock flopping onto his bed, fully dressed.

John climbed in next to him, seeing no other option than to lie half on top of him to avoid falling out of bed.

"You're allowed to change into your pyjamas, you know," Sherlock remarked, raising an eyebrow.

"Boring," John said, not planning to move ever again now he had finally achieved this.

"Okay." Sherlock pulled him even closer and nuzzled his hair.

...

When John was startled awake by a loud shriek, neither he nor Sherlock had moved an inch. Both boys sat up almost at the same time.

"Third-years girls dormitory," Sherlock mumbled, before jumping off the bed and rushing out the door.

Indeed, as they entered the common room, the group of girls that had been giggling at them was standing huddled together outside another dormitory door.

"What's going on?" John asked, quickly throwing a hand over his hair so it didn't look too mussed.

"There's... there's a dragon!" one of the girls managed in a shaky voice.

"A dragon? What, here?" John said incredulously. By his side, he felt Sherlock shift towards the door. "Wait, no, Sherlock..."

But of course, the taller boy had already opened the door slightly to peek in, and a horrible roar met them, making the girls scream.

"Merlin's left testicle," John mumbled to himself. "How..."

"It doesn't matter how now, John," Sherlock said quickly. There was a loud thud against the door and he closed it quickly. "It's going to break out any time now. John, I need you to distract it. I'll find help. You three..." He directed himself to the girls. "Get out of here."

"But..." the shortest girl protested.

"OUT!"

Sherlock ran off, and two of the girls hurried to the common room's exit. The other seemed to hesitate as she looked at John. "We'll guard the corridor," she promised. "Should it get past you... Well..." She bit her lip, shook her head and then quickly followed her friends.

"Right," John muttered to himself. Firmly holding on to his wand, he listened as the beast behind the wall growled and shifted around, though it seemed to leave the door alone for now. He glanced over his shoulder and hoped that Sherlock would find help soon. A bit of danger was always exciting, but John didn't quite look forward to facing a live dragon on his own. Then he thought he heard Professor Sprout's voice in the distance, answered by Sherlock's deep tones. Relieved, he took a step back – but immediately his attention was caught by a loud ripping noise as the yellow door in front of him shattered into pieces and a giant, green head came through.

" _Stupefy_!" John cried out immediately, holding out his wand, but the red beam of light simply bounced off the beast's thick scales. "Sherlock!"

He heard running footsteps, but couldn't take his eyes off the creature that was now driving him backwards, its silvery claws hitching on the carpet. John thought the dragon had to be quite young, as its head only just scraped the ceiling. Then, suddenly, it launched itself forward, snapping at John's injured shoulder.

"JOHN!" Sherlock bellowed somewhere behind the dragon, and Professor Sprout was rambling off a whole stream of spells.

Squeezing his eyes shut, John prepared himself for the pain that would break through his body. Any second now, the beast would bite down... And then there was a breeze of wind past his body and the heat the creature had spread was gone.

Cautiously, John dared to open one of his eyes just a little. There was no sign of the dragon. Only the very confused faces of Sherlock and Professor Sprout in front of him.

"Where... where did it go?" John stammered, reaching out a hand to support himself against the wall and almost landing it on a decorative cactus.

"No idea," Sherlock said, looking very pale.

"I think..." Professor Sprout said, crouching to pick something up from the ground. "I think it's... this." She held up a small, square piece of parchment.

"What?" Sherlock said weakly.

The Hufflepuff Head held her wand to the note and then nodded. "There never was a dragon," she said.

"There never... Professor, didn't you see it?" John asked, for a moment wondering about her mental health.

"I did," she nodded. "But it wasn't real. It was an illusion."

"It felt real enough to me!" John snapped, trying to keep himself from shouting. "I could bloody feel its heat! It was this close to biting me!" He kept his index and thumb almost against each other.

Sherlock burst forward, ignoring Professor Sprout's warning "Wait!", and pulled John against his chest.

"I shouldn't have left you alone," he said, his eyes looking wild.

"Well... At least it didn't leave a jinx with the note," Professor Sprout said, looking a little disapproving at the fact that Sherlock had crossed the distance between him and John without thinking.

"What does it say?" John asked, gently pushing Sherlock off a little so he could at least look at his Head of House – although he gladly accepted that the Slytherin kept an arm around his waist.

"I think it's directed at you two," Professor Sprout said, handing it to John.

He looked down at it and read:

' _Dearest boys,_

 _Well done! You must be sooo proud. Have a little in-theme treat after all that brainwork._

 _I'll be in touch soon!_

 _JM_ '

"Do you know anyone with those initials, who would be in for this kind of prank?" Professor Sprout asked sternly, looking from John to Sherlock.

Both of them shook their heads.

"It... It was some very advanced spell work," Sherlock said, not quite sounding like himself and tightening his arm a little around John. "To make the dragon so real that we could feel it... And to show it in three dimensions without any transparent bits... Showing up only at the moment someone looked in... I don't think I could have done it."

"You don't think it was a student, then?" John understood what he was saying.

Professor Sprout nodded slowly. "You may have a point. We will look into this. It is worrying that someone outside the castle could smuggle a piece of magic like that into a school dormitory. Even if it turns out to be harmless."

Sherlock frowned.

"But why put it in the girls' dormitory if they wanted _us_ to see it?" John wondered out loud.

"Dramatic effect," Sherlock mumbled. "It was a threat."

Professor Sprout held out her hand. "I will take the note to the Headmaster and report what has happened. He can study the spell that was attached and perhaps find some clues to the person who was responsible. It's best if you two go back to bed now. I'll tell Miss Quin, Miss Jones and Miss Gillyweed that they can use another dormitory tonight."

John nodded. "Thank you."

Sherlock took one last look at the piece of parchment before placing it in her hand.

"By the way..." she said as she took it. "Mr Holmes... Why weren't you with your own House? I know you spend most days here, but..."

"Sleepover," John said quickly. "It was a tradition at home that I could have a friend over some time during the Christmas holidays. You know, before... everything. And I... missed it."

"I see." Professor Sprout's expression softened and John almost felt guilty about using her knowledge of his home situation in a blatant lie.

"Well... Goodnight, Mr Watson, Mr Holmes. I will inform you of Professor Dumbledore's findings in the morning."

"Thanks," John said. "Goodnight, Professor."

He looked up at Sherlock, who was looking paler than usual, his eyes set on a point far away. "Sherlock, are you okay?"

Sherlock sharply looked down at him. "You almost weren't," he said hoarsely.

"It was just an illusion. It's fine," John said.

Sherlock shook his head. "It would have been my fault."

John put his arm around Sherlock's waist too and squeezed him a little. "It wouldn't have helped us if you had stayed with me to be eaten by a dragon, certainly if it had been a real one. Getting help as soon as possible really was the best option. And we're fine."

Sherlock took a deep breath and then nodded slowly. "I don't understand how they knew I had solved the case."

"What case?" John asked.

"The dragon smuggling, of course. I haven't even had the chance to inform the Ministry. And there was almost no one around tonight."

John thought for a moment as he gave Sherlock a gentle push, trying to steer him back to his dormitory. "Maybe you should talk to Dumbledore before you write about it. In case this really was a threat."

"Oh, I have no doubt it was," Sherlock said. "But I'll send that Owl anyway. Even if they want to stop us, it'll be better if they don't have the smuggling circuit ready to send us a _real_ dragon, right? And it might provoke them to lay out new clues... JM..."

John smiled a little as he closed his dormitory door. "You're not going to sleep, are you? With a nice new riddle like that on your mind?"

"Oh..." For a moment, John could see something like a small glimpse of panic in Sherlock's eyes. "No, I think I can try. Better to get to work on it tomorrow when I'm rested." He took a step towards the bed, but then stopped. "Actually... There is one thing that I should check. Can you take off your shirt for me?"

John stared and willed himself not to blush. "What?"

"Your shirt." Sherlock rolled his eyes. "I need to see your shoulder. The dragon's teeth would have pierced you, right? What if the spell left something behind? Some kind of tracker, something to listen in on our conversations, to make it even easier to know how far we are in our investigation... Whoever planted that illusion in the girls' dormitory doesn't really need something like that, it seems, but it won't hurt to check anyway."

"Oh. Of course." John quickly pulled his shirt over his head and turned his left shoulder towards Sherlock, who made a scanning motion over it with his wand.

"Looks okay," Sherlock said, repeating the movement with his fingertips. He stopped at the start of John's upper arm and left his hand there, gazing down at him.

"You never actually had any sleepovers at home, did you?"

"No," John said, with a wry chuckle at the thought. "Of course not."

"I'm happy that you asked me to stay."

John studied Sherlock's face, slightly surprised at the remark. "Yeah. Me too."

"I probably never even wished you a merry Christmas properly," Sherlock said, frowning as if trying to remember.

"No, probably not," John smiled. "But that's fine. You didn't have to."

Sherlock shook his head, and before John knew it, he was suddenly very, very close. Close enough to brush his lips softly against John's. Which, making John's heart skip several beats, he actually did.

"Will that do?" Sherlock whispered, as he stood upright again and blinked as if he couldn't really believe what he had just done himself.

"I... Yes," John said breathlessly. "I think that expresses the sentiment quite well."

"Good." Sherlock grinned and flopped back onto the bed.

For a few seconds, John was still staring at him, before a chuckle escaped him and he quickly put on his pyjama top before joining Sherlock.

"You really have no idea who that JM person is?" he asked, resting his head on Sherlock's shoulder.

"No," Sherlock smiled, stroking John's back and looking very happy. "Just that they're something new."

John hummed and nuzzled his neck, deciding that he didn't mind it at all if Sherlock would be thinking about it all night, as long as he wouldn't move out of his arms.

"I'm an idiot, though," Sherlock said after a moment.

"Huh?"

"Riley might have nothing to do with it. If they know exactly how far we got, then it would be very strange indeed if that reporter was anything more than a messenger. Someone who goes to the length of creating that illusion wouldn't make it so easy to find out their identity. But we wouldn't have known that if they hadn't sent us the dragon. So for some reason, they must want me to realise I was wrong."

"Oh," John said. "Do you think they'll gain something from framing Ms Riley?"

"They're not necessarily framing her. She might have _some_ role in it. I just seriously doubt she's leading any of their operations." Sherlock absent-mindedly kissed John's hair, as though they had been lying like this many times before and it simply was what he did.

John blushed at the thought that maybe Sherlock had simply been imagining it as many times as he had.

"You'll sleep here for the rest of the holidays, right?" he asked.

"Of course," Sherlock said. "And perhaps after that. I could make a deal with that annoying guy, what's his name, Anderson. Surely he'll want to leave your dormitory if it earns him a bed next to Wilkes'."

John chuckled. "I doubt the teachers are going to let you two switch Houses."

"Don't be ridiculous. Have you seen Sprout? She'd give us our own flat if she could."

"I do feel a bit guilty about lying to her," John said.

"No need. I think you handled that quite well. And she's got other things on her mind right now," Sherlock shrugged.

"As do you." John smiled and pulled the patchwork quilt over both of them.

"Yes. But you get some sleep, John. I promise I'll wake you up if I get a particularly brilliant idea."

John chuckled. "I don't doubt you will. Goodnight and… merry Christmas, Sherlock." He pressed another quick kiss to the Slytherin's lips.

Sherlock beamed at him. "Merry Christmas."


	2. Back to Work

"You should never have asked me to sleep with you," Sherlock announced as he sat down at the Hufflepuff breakfast table.

John, across from him, glanced around nervously.

"Wait... You slept together?" Bill Murray, who was seated next to John, asked with a wide grin.

"Yes, thank you, I think the entire Hall has heard it by now!" John muttered.

Sherlock ignored them both, obviously impatient to explain his statement. "Returning to my own dormitory was _hell_ ," he said.

"Ah." John couldn't help feeling a little relieved. For a moment he had been afraid that Sherlock regretted the small change in their relationship. "I'm still not letting you bribe Anderson into switching Houses."

Sherlock huffed. "It would make everyone happier and you know it. If the teachers ask any questions, we just explain that Anderson wants a wealthy friend like Wilkes to get on Sally Donovan's good side."

"Of course, blame someone else," Bill said, chuckling. "You're such a Slytherin. Curse you the day it turns out you're only distracting our Beater to make Slytherin win the Quidditch Cup."

Sherlock gave him a look. "If that were my intention, I'd distract your Seeker or Keeper instead."

"And as they are a second and a third years, that would be a tiny bit disturbing," John said.

"So you two have been doing stuff that would be disturbing with second and third years? Wait till I tell the rest of the school." Bill grinned wickedly, but John knew that his fellow Beater was only teasing.

"So how was your Christmas?" he asked him.

"Well, I didn't get to sleep with anyone, but it was alright." Bill winked. He was about to say something more, but Sherlock's owl, Wiggins, landed on the table, holding two envelopes.

Sherlock frowned as he took them and showed John the one with the large stamped M. "Trust the Ministry to take the holidays off before they answer something so delicate," he complained. "No wonder they hadn't noticed the message yet if they waste valuable time like that."

"What message?" Bill asked, but Sherlock ignored him and folded the letter open.

"What a bunch of rubbish," he said, slamming the letter down on the table after only a few seconds. John took it up to start reading it for himself, but Sherlock rolled his eyes.

"Don't bother. They start by encouraging us to keep an eye out and end by saying we should under no circumstances let ourselves be distracted from our studies. In short, they don't know what they want."

"Well, you're always saying you don't need to focus on your subjects to do well..." John said with a smile, bringing the letter close enough to read anyway.

"So I don't focus on them, and instead concentrate on the more interesting things that are happening here," Sherlock pointed out.

As John put the letter down again, he had to admit it was rather meaningless. He pointed at the second envelope. "What's in that one?"

"Mycroft." Sherlock rolled his eyes. "I'm not even going to bother reading that."

John shrugged and took it from the table himself.

' _Brother dear,_

 _Congratulations on your findings about the dragon smuggling. While, as you suggested, Ms Kitty Riley herself won't have arranged the case, we have high hopes that the information we procured from interrogating her will prove helpful. However, you have done your part. It is now much more important that you prepare your N.E.W.T.s with the same, if not more, dedication as before. Besides, the spell-work you witnessed in the early hours of Boxing Day has shown how dangerous it can be to meddle in this business. So please, Sherlock, relieve the worst of my worries and back off._

 _I wish you and John a good start of the new semester and a happy new year._

 _MH'_

John was startled by the hand on his shoulder as Sherlock leaned in to read it, now standing behind him.Really, he should have known better than to think Sherlock could keep his curiosity in check.

Resting his cheek ever so slightly against John's, Sherlock snorted. "Clearly Mycroft doesn't know the effect 'could be dangerous' has on you. This is a plain invitation to keep investigating."

"I'm not sure it's meant like that. After all he _does_ worry about you," John said. "But it doesn't matter what he says anyway, so..."

"Investigating _what_?" Bill asked, trying to see the letter, but Sherlock plucked it out of John's hands and stepped aside. A moment later, another voice came from behind John's back.

"Watson. Murray."

John and Bill turned around on the bench to see their Quidditch team captain, James Sholto. The tall, strong Chaser was giving them his usual, oddly approving nod, and a quick glance at Sherlock's face told John that of course he was sulking at the very sight of him.

"We're up against Gryffindor next, so I'm sure you understand we'll be starting training tonight," Sholto said.

"Oh. Sure," John said. "Seven o'clock as usual?"

Sholto nodded again and then turned to go sit with his seventh-year friends at the end of the table.

"You're staring at him," Sherlock remarked coolly.

"What?" John's gaze snapped up at him. "Of course I'm not. I was just thinking about the training. He'll probably clutter my whole schedule again. Which is fine, but I need to be prepared for working around it to get my homework done and... you know. Have time left for running after you."

"And your eyes had to be resting on his lower back to manage those thoughts?"

John huffed out a laugh. He honestly hadn't even noticed. "Sherlock, are you jealous?"

Sherlock crossed his arms. "Why should I be?"

"Never mind the cap's bum," Bill said. "Is someone finally going to tell me what you're investigating?"

...

As John told Bill about the dragon in the girls' dormitory, Sherlock pressed himself into the small space between John and a fourth-year. He didn't eat properly, of course, but stole a few pieces of bacon from John's plate and poured himself a cup of tea. John enjoyed the way their sides were pressed together, but mostly ignored Sherlock, catching up with Bill and Mike Stamford. However, when they had finished their food and were getting up to go to the first lesson of the day, Sherlock took hold of John's arm.

"What is it?" John asked, sitting down again and turning towards Sherlock. He frowned as he saw the thoughtful look on Sherlock's face, wondering if there was something he had noticed in the letters that he couldn't have told him while the others were listening in.

Sherlock squirmed a little. "I just... I wanted to wish you a good day."

"Erm... Alright," John said. "You too."

Sherlock still looked like there was something he wanted to say, and finally John realised. They had been together constantly, even at night, since Christmas. Clearly, returning to his own dormitory now their fellow students were back didn't sit well with Sherlock. And now they were splitting up again for their lessons.

"You do realise we'll be seeing each other this afternoon in Potions, right?" John asked.

"Yes... But why don't you come along to Arithmancy? It'd be much nicer," Sherlock said.

John smiled a little, taking his hand. "I'm sure it would be _nicer_ , but Professor Flitwick probably wouldn't think that a good excuse."

Sherlock huffed. "I really don't see why you have to take Charms. You're already charming enough."

"Nice try," John said, chuckling. "I'm not giving up my possible career as a Healer to listen to... whatever it is you do in there with those numbers."

Sherlock's pout was even worse than when Sholto had come to announce the Quidditch practice, so after a quick look around the Hall, John leaned in and pressed a quick kiss to his cheek.

"You'll survive a few hours without me."

"If you say so," Sherlock muttered, but he looked a little happier when they left the table.

...

When John sat listening to Professor Flitwick's explanation of Fountain Charms, he almost regretted not joining Sherlock. Not because the charm wasn't interesting, but... Apparently he, too, had grown all too accustomed to the other's constant company. And he wished he'd taken more time to discuss the letters with him. Sherlock might be scolding the Ministry for taking time off, but to be honest, it wasn't like they had investigated much either. On Boxing Day they'd stayed in bed until late in the morning, cuddling with the excuse of Sherlock needing to think. However, John had had the feeling that it was much more about reassuring them both – not only because it had looked like the dragons' claws would tear John apart, but also because they were nervous about the kiss they had shared that night.

In the late afternoon, a note from Dumbledore had reached them, but it had been about as vague as the Ministry's.

All that day, they hadn't kissed or even talked about it. Sherlock treated John just the same as always, and although John knew that Sherlock would stay the night, he wondered if kisses would be something rare between them, or maybe even something that only occurred at Christmas. In hindsight, he suspected he'd been staring at Sherlock's lips quite a few moments that day, but the fact that Sherlock didn't comment on it seemed to imply that he had no desire to repeat it.

Only when they went to bed around midnight, Sherlock had given him that slightly puzzled look and said: "John?"

"Yes?" John had answered.

"That... That thing we did yesterday. Was that... okay?"

"Do you mean..."

And then, somehow, no more words had been needed and John had pulled Sherlock in for not just their second, but many more kisses. From that moment on, it had become a natural thing to do, just like the hugs and the smaller touches that John now realised had already been more frequent than he'd known.

"Mr Watson," Professor Flitwick squeaked. "Did you hear anything of what I said?"

John blinked. "Er... Fountain Charms. Yes."

A few people giggled, so probably Professor Flitwick had long moved on to a new subject. Oops.

The small teacher just raised an eyebrow and said: "Please try to stay with us. You've had the holiday to daydream, now it's time for some work."

Mike Stamford winked at John with a knowing smile and John huffed, wondering how many students already knew about him and Sherlock. Not that he cared, but... The way none of them was surprised gave him the feeling he'd done a lot of worrying for nothing. And wasted a lot of time before finally acting on the way Sherlock could turn into the brightest thing in the room just by saying something, making his heart skip and ache with the need to pull him close. And damn – putting it like this in his head made him sound like the soppiest idiot ever. He really should pay some attention to the lesson, but now he was just looking forward to lunch time and wondering where he should sit to make sure he could catch Sherlock for a quick hug before the Slytherin returned to his own classes or dashed off to the library.

What he had not expected was that Sherlock would be waiting for him in the corridor after Transfiguration – another subject Sherlock believed he could learn well enough on his own or by reading John's notes.

"John," he said immediately, grabbing John's arm as soon as he could reach him. "We're going to the library."

"Oh?" John said, trying to close his bag one-handed. "What about lunch?"

"Lunch can wait!"

Of course Sherlock usually felt that way, but for now John would indulge him. After all he did have a free period in the afternoon, so as soon as Sherlock was off for his Alchemy class, John would be able to get something to eat.

"So what's so urgent?" he asked, allowing Sherlock to drag him along.

"The illusion, John! I can't believe I've been so idle... Should have realised immediately..."

John frowned, wondering what new discovery Sherlock could have made about the dragon in the hours since breakfast. "Did you gather something from those letters after all?" he asked. "Because, you know, I've been thinking too... What if it's not us Mycroft wants to protect, but also the other students? I mean, no one else was around when it happened. And it didn't look like third-years magic, but what if one of them does have something to do with it?"

Sherlock had stopped and stared at John. "What are you talking about?"

"The... the illusion..."

"The _Drought_ of Illusion, John! My Alchemy homework! For once we get an interesting project and then I ruin it by actually following the instructions. I've been a fool! I may have made the discovery of the century!"

" _You_ 're talking about _homework_?" John reached out to feel Sherlock's forehead, but he didn't seem feverish. "Homework, when there's a _case_?"

Sherlock huffed and batted his hand away. "It's interesting. The kind of thing I might be investigating anyway, though if I weren't at Hogwarts, I wouldn't have the right sources to prove my point. And when it comes to our case... There's no new data. So I may as well focus on this."

John snorted at his self-righteous expression. "So what do you need me for? The way you were dragging me from my lunch, I was sure I could help you with something."

Sherlock's face fell. "Don't you want to come?"

John couldn't help grinning. "Of course I do, you idiot. You could just have asked for my company without acting all mysterious."

"You like it when I act mysterious," Sherlock pointed out smugly.

John rolled his eyes and followed him.

...

"What you said," Sherlock said that evening, and John glanced sharply at his dinner plate, making sure the other boy knew he'd realise if he was just distracting him from whether he was eating or not. However, Sherlock didn't seem to notice and even took another forkful of peas before he continued: "About someone here needing to be involved. I've been thinking about it too. I mean, it's obvious _someone_ was involved. With all of Hogwarts' security measures, it's impossible to just send something like that from the outside. But it doesn't make sense that it's a couple of third years, John. Not with that sort of magic."

John nodded. "I know. It's just... None of it does make any sense, does it?"

Sherlock shook his head, and again there was a hint of that smile that betrayed how intriguing he found it all. "Let's hope we come across a new clue soon."

John nodded, then put down his fork. "I'm getting a _bit_ worried," he admitted.

"What?" Sherlock frowned at him.

"We've just spent all of Potions working next to each other and you haven't said a _word_ about Alchemy. Not one. I thought you'd be gloating about your discovery of the century."

"Oh." Sherlock wrinkled his nose. "It wasn't... It wasn't that great."

"Modesty?" John asked. "Now I'm _really_ worried."

"I was wrong, alright? Is it really that great to hear it?" Sherlock snapped, aggressively stabbing his fork through a piece of battered fish.

John actually felt a little taken aback. "Sorry," he muttered. "I didn't mean to rub it in or whatever. You were so sure, so... I thought you were just saving up your grant story."

"Well, there isn't one," Sherlock said, letting go of his cutlery and crossing his arms. "Apparently dozens of people have had the same idea as I had and they all came to the conclusion that it wouldn't work. I should have known better than to make the same mistake _everyone_ makes."

John reached over the table to put a hand on Sherlock's wrist. "Hey. It's not that bad. I'm sure your next mark will make up for it."

"That's the worst part," Sherlock huffed, though he did turn his hand so he could rest his palm against John's. "Professor Bell gave me top marks. Just because I had thought of it. It's absolutely ridiculous. They're enforcing the idea that we are just small children who can only repeat what has been said before. The idea that nothing is ever new. Doesn't it drive you mad?"

John smiled and stroked his hand. "You came up with a theory that alchemists who have studied these matters their whole _lives_ came up with, while simply doing your homework. And if they'd given you another day, you'd have discovered the mistake and perhaps – probably, even – set it right. As the very first one. I wouldn't be insulted that they're proud of you, Sherlock."

Sherlock rolled his eyes.

"I'm proud of you, too." John squeezed his hand, and finally the other boy relaxed.

"And now I really should go," John said. "Quidditch training is in ten minutes and I still need to pick up my stuff."

Sherlock groaned. "Do you still have that ridiculous rule that 'spies' from other Houses aren't welcome?"

"Sorry, Sherlock," John said, walking around the Hufflepuff table so he could give him a hug. "I guess my team _really_ can't imagine how much you're not interested in the best sport in the world."

"'m interested in its players," Sherlock muttered, but in the end he let John go.

...

As expected, Sholto had prepared a very full practice, claiming that they needed the extra training after two weeks of eating and lounging. He might have a point, but John felt that a more gradual approach would have worked better for his injured left shoulder. It had been two years since he was knocked off his broomstick during a match against Gryffindor, but especially when it was cold, the muscles easily got stiff and achy. He was rubbing them, rather frustrated at the thought he still had to write a short Potions essay that night, and Bill threw him a few worried looks as they approached the Hufflepuff common room.

"I'm fine," John assured him. "It'll get better when we've had a bit more practice. And when it's warmer."

"You should take the night off or something. Take care of yourself. We can't lose our best Beater."

"Oh, something wrong with you, then?" John asked with a wink.

"No, but seriously..."

"He's right," Sherlock said, stepping out of the shadows next to the stack of barrels in the nook of the kitchen corridor.

"Holy crap, you scared the hell out of me!" Bill cried out, actually jumping back a little.

John couldn't help smiling. "Hey. Here to say goodnight?"

"I could send Wiggins for that," Sherlock answered, rolling his eyes and disappointing John just a little bit. "I'm here for your shoulder." He reached into his pocket and held up a small bottle of oil – making John forget what disappointment even was.

"I'm... not sure I want to know," Bill said, glancing at the bottle and then quickly moving on to the door.

Sherlock rolled his eyes. "I'm just taking care of your Beater."

"Thanks. Still don't want to know." And he disappeared past the barrels.

"Don't mind him," John said, beaming at Sherlock. "You are amazing, you know that?"

"Can't forget for very long with you around," Sherlock answered, smirking down at him. "We have half an hour before I need to get back. Dormitory?"

"God, yes."

...

"Sherlock..." John groaned. "Hell, that feels good. Just... Just a little low-aaaarh..."

"John," Sherlock said drily, "heaven knows I don't care, but if you don't want your friend Bill to blush every single time he looks at one of us in the foreseeable future, you may want to keep it down."

"Oh." John realised how he sounded and blood rushed to his face. "Sorry. It's just... I think your hands are magic."

Sherlock snorted and dug his fingers a little deeper into John's shoulder muscles, working out the last knots. "No magic involved here. Just a good grasp of anatomy."

"You certainly do have a good grasp," John quipped, looking over his shoulder for a moment.

"Sometimes your sense of humour is just atrocious," Sherlock said, rolling his eyes, but John recognised the fond twinkle in his eyes before he was pushed back into his pillow. "Stay still. I can't work on your muscles if you keep tensing up."

"Now that didn't sound wrong at all," John muttered into the feathers.

Sherlock continued his massage a few minutes longer, and then got off John's legs. "Better?"

"Much. But that doesn't mean you need to stop," John said, turning onto his back to look at him. He could have sworn that Sherlock's eyes lost their way from his chest up to his eyes for a moment.

"I wouldn't if I didn't have to return to my own dorm."

John sighed. "We'd get in trouble if you stayed."

Sherlock nodded. "Could be dangerous."

"It will stop working if you keep using that."

"No, it won't." Sherlock smiled and stretched out next to him. "So I can stay?"

John huffed and decided to avoid answering by putting a hand on Sherlock's neck and drawing him closer. Their lips had barely had the chance to touch when the round door opened.

"Ewwwww! Merlin's beard, you two can't be _serious_!"

Sherlock fell back on the narrow mattress, somehow not tumbling to the floor. "Anderson, don't talk out loud. You're lowering the IQ of the whole floor."

"But honestly!" Phillip Anderson wailed. "In our dorm!"

John sighed and got to his feet. "We're _dressed_ , Phillip. Well-" he looked down at his bare chest – "mostly. Point is, we weren't doing anything. Just lying down."

"You were _kissing_!" Anderson accused.

"Such horror," Sherlock commented.

"I'm not that bad," John said with a shrug.

Anderson shook his head. "I don't believe it. And with the freak!"

John's wand was in his hand before he had time to think about it. "Now, Phillip, call Sherlock that again and you'll have a reason to be disgusted. By the trail of slime that will be all that's left of you."

"John," Sherlock said warningly, but John didn't lower his wand and glared at Anderson until he'd stepped in his bed and pulled his curtains shut.

"John," Sherlock repeated, softer this time.

"I can't just let him call you that," John snapped. "He's only parroting that oaf of a Donovan because he wants to be disgusting with _her_."

"I know," Sherlock said, stepping closer. "I just... It's, er... good. To know that you..." He shrugged.

"That I what?" John asked, a little amused. "Stop thinking at all when there's a reason to defend you?"

"But you don't," Sherlock said, tangling their fingers. "You do exactly what is needed to shut them up, but you don't do anything foolish. And you don't even realise how brilliant that is."

"Oh." Not sure how to handle _Sherlock_ telling _him_ he was brilliant, John grabbed a handful of curls and pulled him into another kiss.

"I should go," Sherlock said when they broke apart.

"Yes, you should!" a huffy voice sounded from behind the curtain, making John snort.

"Goodnight, Sherlock."

"Goodnight, John." With another soft kiss, Sherlock left the room.


	3. Mermessage

_Note:_

 _Before you read on, I want to tell you to consider this story a kind of AU where Voldemort was properly defeated after the First Wizarding War (or at least that's what everyone believes – you never know). That means that at this point Harry Potter is a fairly ordinary third-year student who doesn't get in quite as much trouble, that Sirius and Remus are happily living together, and all kinds of other nice things, so I'm sure no one will really complain._

 _The reason I need to point this out is that, going with Sherlock's date of birth in January 1977 as given in_ Sherlock Chronicles _, this story is taking place in 1994. (John is still older than Sherlock, being born in September 1976, just in case you were wondering.)_

 _But some things from the_ Harry Potter _universe just wouldn't fit into the plans I had for this story. Hogwarts couldn't be swarming with Dementors, so Sirius Black couldn't have escaped from Azkaban, which avoids that Sherlock gets completely distracted by his case. And the Quidditch teams look quite a bit different, since I have inserted other characters._

 _I want to thank Fie for the pondering peony, Tanouska for making some sentences flow better and Jlocked for keeping my Sherlock in character. And thanks to the lovely people who left reviews. I can't answer in person to the guests who don't have an account, but know that your kind words are dearly appreciated!_

* * *

 **Chapter 3: Mermessage**

"John, there was a merman in my shower." Sherlock was looking very pale as he sat down at the breakfast table.

"You... What? Sherlock..." John started sternly.

"I haven't been drinking any of my own potions," Sherlock said immediately. "It was really there. Look."

He plucked a piece of parchment from his robe and laid it down in front of John.

' _Dear me, Mr Holmes, dear me,'_ it said. _'Such hard work and not even a pat on the back from brother Mycroft. You must be sooo disappointed. But here's a little puzzle to cheer you up. JM'_

"This JM person is sending messages to your shower?" John asked, looking up from the note.

"Suddenly it was just there," Sherlock said, still looking uncomfortable. "Another illusion, just as real as the dragon was."

"In your _shower_?"

Sherlock frowned a little. "Yes, John. I've told you as much."

"So they had to know which shower you picked, when you'd be there, when you'd be _naked_."

"Obviously." Sherlock shrugged.

"What did this merman look like?"

The slightest tinge of red crept to Sherlock's cheeks. "Well, he didn't look like a _proper_ merman. More like the pictures in my father's books with Muggle fairytales. He was blond and... fit..."

"Oh, fantastic. Doesn't that sound just great." John pushed his plate away and crossed his arms so he'd stop clenching and unclenching his fist.

"He... It only said a few words to me," Sherlock said. "Before it turned into this note, I mean. In English, not Mermish. And it didn't make much sense."

"What did it say?"

"'Can't wear shoes now that I've got fins. Good thing too, but it's too late to save me from my sins,'" Sherlock quoted.

"And did it leave anything else? That 'little puzzle' JM is referring to?" John turned the piece of parchment over, but there was nothing on the back.

"I suppose the remark about the shoes _was_ the puzzle. But I don't get it," Sherlock said. "And... I'm worried."

John raised his eyebrows. "No shit. Someone can send pieces of advanced magic to a place as private as your shower. You _should_ be bloody worried!"

"That's not what I mean." Sherlock swallowed and held out his hand for John to take it, which he did, frowning.

"The merman... He looked like you, John. Not quite the same, but there was so much in his appearance that reminded me of you. And then he tells me that it's too late to save him. This JM person is dangerous, that much is clear. If they can send us these illusions, they can just as easily send spells that can actually hurt us without even needing to come close. I don't want you to get hurt, John, but it sounded like a given that you would."

John exhaled, the edge disappearing from his anger, and squeezed Sherlock's hand. "I'll be fine. You just said it's a puzzle. Maybe they only made it look like me to make sure you'd listen. JM must know you rather well." He smiled a little. "Besides, I don't think I've committed that many sins. It might be about someone else. Someone who's famous for their shoes and who's passed away, I assume."

Sherlock breathlessly stared at him for a long moment. "You're right," he whispered. "What's wrong with me? How can I be so blinded by sentiment when the challenge is so obvious? A merman in a shower – it could only have been clearer if they'd actually dumped me in the lake myself! And missing shoes, someone who couldn't be saved... This is about Carl Powers."

"Who the hell is Carl Powers?" John asked, irrationally thinking that if Sherlock had a blond, fit swimmer for an ex-boyfriend it would have been nice if he'd told him.

"He died seven years ago. In the year before we started at Hogwarts," Sherlock said. "Mycroft was still at school, so he told me all about it at the start of the summer holiday, as it happened at the end of the school year. Little Carl was a first-year from Gryffindor. It was a really hot summer, so he and his friends went for a swim in the lake. But he never surfaced. They did retrieve his body with the help of the giant squid, but it was a mystery what had happened. He'd been in swimming competitions in his Muggle school before he started at Hogwarts, so he couldn't just have drowned. And it wasn't a dangerous part of the lake; all his friends were just fine. In the whole story, there always was one thing in particular that bugged me. His shoes had disappeared. But no one seemed to think it was important. Even Mycroft couldn't get his boring mind to see past the obvious. It couldn't simply be some kind of odd accident, but he felt that it was his duty as my brother to teach me that 'bad things happen sometimes', as though I was unable to deal with facts just because I was eleven years old."

John frowned. "I must say, I'd expect that people had looked into such suspicious circumstances. If they didn't find anything, they must have assumed that you had a rather wild imagination."

Sherlock huffed. "Well, they were idiots. Clearly there is more to it, or I wouldn't have received this message. It actually says that it's lucky he's not wearing shoes, so there must have been something about them. JM, whoever they are, must want me to solve Carl Powers' murder. The question is why. Are they a witness who wants the truth to be revealed, or the murderer who wants their work to be acknowledged?"

John nodded slowly. "So... Will you be working on this? Should I make an excuse for you in Herbology?"

Sherlock blinked. "How do you always do this? How can you say the exact right thing that I need to hear?"

"I'm great?" John shrugged. "So you won't be coming to the greenhouse?"

"No, I'll definitely come," Sherlock said. "I think it might be exactly the place where I need to be."

...

"You should talk to Professor Dumbledore about this!" Professor Sprout whispered fiercely as Sherlock showed her the new note after a quickly whispered explanation.

While most students didn't seem to notice their exchange, John found it rather hard to focus on potting his pondering peony while there was something so interesting to overhear. But he didn't have much to add and he wished to remain on his Head of House's good side, what with her allowing Sherlock in the Hufflepuff common room, so he scooped away some earth while stepping just a little to the right, hoping to hear more.

"I know," Sherlock was replying, "but I need your help first, Professor. Do you remember Carl Powers?"

Professor Sprout was frowning at him, clearly a little shocked. "Of course I remember the poor boy. How... What does he have to do with this?"

Sherlock explained what he had told John earlier, so John decided to pay attention to the peony for a moment. It had started to hang its head, so he quickly stamped the earth closer around it and watered it with his wand.

"Say, hypothetically, that you want someone to look fine until the very last moment," Sherlock said. "Until they step into the water and they just... become very heavy, or forget how to swim, something. Is there a plant that could do that?"

"I hardly think I should answer that question," Professor Sprout replied, raising her eyebrows.

Sherlock rolled his eyes. "Carl's shoes were never found, were they?"

"No," Professor Sprout answered.

"I imagine the killer made sure they couldn't be found because they did something to them, something that was fatal to Carl, whether it was a curse, a potion, a plant or something else."

"The killer?" Sprout repeated. "Mr Holmes, you can't just assume from this that Mr Powers was murdered. Don't you think we have looked into the matter? It was a sad affair, but there was _nothing_ that pointed to ill intent."

"Except the missing shoes!" Sherlock enunciated. A few students looked up, clearly wondering what kind of fuss he was making this time.

"Please focus, everyone," Professor Sprout asked them. "You know the pondering peony is a delicate plant. Soft touches will have more effect than brute force."

John huffed and stopped trying to pull open the bud of his peony while Professor Sprout directed herself to Sherlock again.

"The shoes may as well have been stolen by some animal that roamed the grounds," she said. "I don't know why your mysterious writer wants to make so much out of an accident – if it's about the late Mr Powers at all. It was just one sentence and a note, so this could be about anything. I don't know why this person is so keen on distracting you, but you shouldn't let them."

Sherlock groaned. "You can't _actually_ still believe it was an accident. I understand that you and the other teachers didn't want to admit your incompetence to Powers' parents, but when all the evidence points to murder, I'm still supposed to accept that this just _happened_?"

"Sherlock," John said warningly, making rather clear that he wasn't petting his peony.

"Mr Watson, you may as well join the conversation if you're eavesdropping anyway," Professor Sprout said wearily. The other students were looking up too, clearly getting tired of the green knobs they were supposed to woo. "And everyone else pays attention to the lesson!"

"Maybe we should discuss this later," John muttered as he stood with them.

"We can't, John. It's urgent," Sherlock objected.

"It's years ago," Professor Sprout said, crossing her arms. "You really should let this go."

"Do you think it'll all stop if I just ignore this? Do you think there is no chance at all that they would make good on their threats?" Sherlock hissed.

Professor Sprout sighed. "As I said, talk to Professor Dumbledore. If there is any real danger, that's all the more reason not to let you get involved. You're still our students, Mr Holmes, Mr Watson. Now please... You will be making yourselves _far_ more useful if you can collect some pondering peony pollen. It's an important ingredient in the memory-strengthening potions that you will soon be studying and who knows, maybe those may actually help you if you're investigating an accident from seven years ago."

Sherlock huffed and turned away from her. As he and John were standing near their peony pot again, John gave his shoulder a comforting pat and then decided to try the same on the peony bud. The leaves unfolded slowly, giving him access to the stamens.

...

Sherlock strode off as soon as Professor Sprout announced the lesson was over, leaving John to do a sort of half-skip in order to keep up with him.

"Where are we headed?" he asked when he'd caught up.

"I need to ask some advice," Sherlock said.

"What?" John looked up at him and couldn't quite hold back a grin. "Sorry?"

Sherlock rolled his eyes. "You heard me perfectly. I'm not saying it again."

"You need _advice_?"

"On stolen shoes, yes," Sherlock said. "I need to talk to an expert."

"Wait, Sherlock, we're not going to talk to Filch, are we?" John wrinkled his nose.

"Really, John. Carl's cause of death was almost certainly magical, so Filch could hardly help. And if, back in the day, he'd found Carl's shoes, he'd have given them to the teachers. But I'm not surprised he didn't. He can't even keep track of his own buckets."

"So... who?"

But Sherlock didn't say another word all the way to the fifth floor, where they stopped next to a door with a bronze, eagle-shaped knocker.

John frowned. "You think Molly spends her free time stealing shoes?"

"Not Molly," Sherlock grumbled.

"But –"

"Hello," a soft voice said behind them.

John turned around and saw a very short, wispy, pale girl with dirty-blond hair and large, grey eyes looking up at him. "Yes, hello, can we help you?"

"I thought you were here to _find_ help," the girl said, studying John's face as though she expected that some kind of code was hidden under his skin.

"We are," Sherlock said. "John, this is Luna Lovegood. And _yes_ , she's old enough to be at Hogwarts. In fact she's in her second year."

John swallowed the question he had been about to ask.

"Luna, John Watson," Sherlock continued. "We want to ask you something."

The little girl nodded earnestly. "Go ahead."

"Last year you told me that your stuff kept going missing," Sherlock said. "Especially your shoes."

Luna nodded again. "They are often stolen by Nargles."

"Right..." Sherlock sighed. "When they're returned, do you ever notice that there's something wrong with them? Some kind of change that only occurs as soon as you put them on, but couldn't be noticed before?"

The girl shrugged. "One time they'd been hidden outside so there was some sand in them. But that's not what you mean, is it?"

"No," Sherlock said. "I'm talking about magical changes. Spells to make them change colour, some kind of curse..."

"Oh, I'd love if they'd change the colours every time," Luna interrupted happily. "Maybe I should drop that idea sometime at the dining table... It would be so interesting to see what they came up with, and they'd learn something new."

"Who, the Nargles?" John asked, but Sherlock gave him a look and Luna just giggled.

"So far the thefts have been quite ordinary," she told Sherlock. "It hasn't even happened much since that time last year."

"Good," Sherlock said, "but then you're not much use to me right now." He turned and started walking off, but Luna said: "What are you looking for?"

Sherlock swivelled round again. "Why do you think I'm looking for anything?"

"You wouldn't come all the way here between lessons to ask about my shoes if you didn't have a special reason," Luna pointed out. "What did you think might have happened to them?"

"Any kind of prank," Sherlock answered. "Something students find funny. It might have inspired someone when designing Carl Powers' murder."

"Oh. You're investigating a murder." If Luna was shocked that this reminded Sherlock of her, she certainly didn't show it. "How did he die?"

"Carl died in the lake in his first year at Hogwarts," Sherlock answered. "We don't know yet what exactly happened to him."

"Have you considered Aquavirius Maggots?"

Sherlock took a deep breath, clearly starting to lose his patience.

"You're right, it wouldn't have been easy to keep those inside a pair of shoes, they'd just wriggle out." Luna nodded thoughtfully. "What makes you think his shoes were involved, though?"

"They went missing," Sherlock said.

"How long ago?" Luna asked.

"Six years and six months."

"Hmm..." she said. "So you're saying that every trace of what happened to them has worn off after so much time? Or that the changes disappeared as soon as Carl wasn't wearing them anymore?"

"No." Sherlock scowled. "I'm saying that I don't have the shoes, so I can't simply study them."

Luna blinked owlishly. "Why aren't you looking for them? They must be somewhere. It will be much easier to form a theory when you've had a proper look."

"Yes, thank you," Sherlock said irritably. "Any thoughts on where a sporty eleven-year-old's shoes may have been stored for such a long time?"

John rather expected that the girl would admit that they could be anywhere, but she just narrowed her large eyes for a moment. "Are you sure they have been in the same place all the time? I sometimes find my shoes just because they were in someone else's way, or because the one who hid them got bored of them being in that place. There's no fun in it if I never find them, because then they can't be hidden again."

"It is a possibility that the murderer took them somewhere else first, yes," Sherlock said. "But..." He fell silent. "Actually... It would make sense if they're somewhere I'd think of. Hidden in plain sight, but without being noticed by anyone who isn't me. Clearly JM knew about the shoes' importance, so..."

"Well," Luna said, "there are a lot of hiding places at Hogwarts, so the question is which of them is most suited for shoes like that. In fact, my father told me once that Professor Dumbledore accidentally invented an evil pair of brogues that eats the wearer's toenails right off their toes, and that he keeps it somewhere under the castle. That's not the one you're looking for, is it?"

Sherlock raised an eyebrow. "Please save us your father's idiotic notions."

"Anyway," Luna said cheerily, "I think you should focus on finding the shoes first, and _then_ on how they were used. If you keep focusing on too many things at once, you'll only attract more Wrackspurts."

"Yes, thanks for the tip," Sherlock said impatiently.

"You know where to find me if you need any more help," she said. "But break's almost over, so I should get to Transfiguration now."

Sherlock nodded and made a sort of dismissive wave.

"There are so many places where they could be on these grounds," he muttered to himself. "Somewhere in a harness or a chest in the corridors, under a loose stair step, buried in the Forbidden Forest, or simply between all the other shoes in a dormitory wardrobe… But the one thing we know is that Carl Powers drowned. The note was sent to a shower, so if we stay in theme... If we want a wet place where no one enters if they can avoid it, that isn't the lake… After what happened last year, I'd think of Moaning Myrtle's bathroom, wouldn't you?" He looked sharply at John, who was still following Luna with his eyes, her hair dancing as she skipped out of the corridor.

"Sounds plausible," John said. "So… We're spending our free period visiting a girls' bathroom?"

Sherlock smirked. "I think we are."

…

"How do you know her?" John asked as they descended the stairs.

"Hm?" Sherlock still seemed lost in thought.

"Luna. Did she come to you to find some of her lost stuff?"

"Oh, no..." Sherlock shrugged. "She's perfectly capable of finding it all on her own."

"So how?"

Sherlock sighed. "I was in the library last year when some of her classmates were ganging up on her. Not physically, but... You know. Calling her names, acting superior, you know the drill. So I cursed them."

"Oh." John studied his face. "You... cursed them?"

"Do you need to repeat everything I say today?"

"No, it's just…" It was just that it didn't sound like Sherlock to lose his temper over someone he didn't know, didn't care about. But now that John gave it more thought, he supposed it made sense. He of all people knew that Sherlock _did_ care about others. And if they were being bullied… Sherlock wouldn't stand for that. He knew too well what it was like. "Never mind."

"She's an intriguing little thing," Sherlock said, the corner of his mouth tugging into a smile. "She said she was grateful and then pointed out four ways that would have been better to handle the situation. I can't agree with the way she believes things for which there is no proof whatsoever, and yet there is wisdom in her theory that the realm of possibility is not always as black and white as we make it out."

"So you like her," John said.

"She's alright. Let's just hope she never gives in to those who want to force her to 'fit in'. She'll get far with that brain of hers if she keeps taking good care of it."

They went the rest of the way to the first floor bathroom in silence, and after John checked the corridor a few times, he opened the door cautiously.

"So where are we supposed to find them?" he asked, looking around at the chipped sinks and the dirty floors. "There isn't really anything around where you can put shoes, right?"

"Of course there is," Sherlock answered, pointing at the flaked wooden doors and giving him a sometimes-I-can't-believe-what-an-idiot-you-are look. "For one, there's the rubbish bins."

John made a disgusted sound.

"Problem?" Sherlock asked.

"Well..."

"Oooooh," a girl's voice sounded, and a moment later the ghost of a squat girl with thick spectacles floated up from a pipe. "I'd tell you this is a bathroom for girls, but _you two_ probably know. Looking for a little privacy?" She winked.

John fell silent and glared at her. "Excuse me?"

"Oh, don't be ashamed in front of me," she cooed. "I won't tell anyone. I'll just sit here very quietly. Go ahead." She flapped her pearly hands. "No need to hold back here."

Sherlock raised his eyebrows. "Believe me, if we wanted to _do_ anything, we could think of dozens of more private places that also have the advantage of a less repulsive smell."

"We could?" John asked, eyeing him curiously, but Sherlock gave him a look.

"So what _are_ you here for?" Myrtle asked. "You don't look like the types that will start making potions in here... And you won't be here to visit poor miserable Myrtle..."

"None of your business," John snapped.

"A pair of shoes," Sherlock said.

"Ha. Ha." Myrtle rolled her eyes at Sherlock. "So you're the funny one?"

"No, we're actually looking for a pair of shoes. Carl Powers'."

"Oh, I saw him once," Myrtle said, pulling a face. "He was a nasty one."

John frowned. "Was he?"

"A bit of a bully, yes. Of course, when I was comforting his victim, that one did turn out to be a bit of a nutjob. I can't really remember his name. He was handsome, though. There was something about that boy. He was so..." She shrugged. "And his voice. He always sounded so... soft."

"Right," Sherlock said. "All massively interesting, but let's get to the point. A pair of shoes. Possibly hidden in here. Ring any bells?"

"What's in it for me if I help you?" Myrtle asked.

"Honour?" Sherlock suggested. "You're dead, whatever could you want?"

Myrtle huffed. "I may be, as you so sensitively put it, dead, but that doesn't mean I can't have any little pleasures anymore."

"So what _do_ you want?" John asked.

She smiled triumphantly. "You two are going to kiss."

"What?"

"Oh yes. A proper snog, and I get to watch."

"No way," John said, actually taking a step back.

"Oh, come on, don't be silly," Myrtle said, pouting. "You can't say I'm asking a lot. And you'll get something in return, because I know no one would actually do something for _me_... I'll be very discreet. Though everyone can see from a _mile_ that you two dishy boys are together... I just want to see it happen."

John turned to Sherlock, feeling rather hopeless. "How is everyone so bloody observant all of a sudden? Didn't you always say no one ever notices anything? How?"

"Well… It's not that horrible a price, is it?" Sherlock asked. "If all she wants is to see a kiss…"

"A _proper_ kiss," Myrtle corrected.

"I don't like her watching!" John protested.

"Oh, just the two of you arguing like this makes me wish they'd invent popcorn for ghosts," Myrtle commented, leaning back in the air as though she were settling in a sofa.

"Let's just – get it over with," Sherlock said, and he stepped in and cupped John's face in his hands.

"But –" John's complaints died down as Sherlock's lips were pressed to his own and he melted against the taller boy. A full two minutes later, they let go of each other again, and John had forgotten all about the ghost until she spoke.

"Well, that _was_ quite the show," she said, a silvery blush on her cheeks. "Whew."

Sherlock raised a demanding eyebrow. "Shoes?"

"Yes, yes," she said. "It's rather odd actually. That they're Carl's, I mean. They've only been here for a couple of days. Put here by a girl."

Sherlock's gaze snapped up at her. "A girl? Who was it?"

Myrtle shrugged. "I don't know her name. Dark hair, pale face, not very tall…"

"That could be anyone," John sighed.

"And it's probably not the killer," Sherlock said. "Either the girl is JM, who got hold of the shoes somehow, but more likely JM is the killer, who must have held on to the shoes for all those years and then either brought or sent them here, so the girl could plant them somewhere we'd find them."

"It would still help if we knew who'd actually put them here, right?" John said. "Even if it's not JM, she must be in touch with them."

"I could keep an eye out for her," Myrtle said. "Tell you how to find her."

"That would be kind," Sherlock said, and she giggled.

"Kind? Oh no. It would take time, so the price would be higher than just a tiny kiss."

"No thanks," John said pointedly. "We'll find out ourselves who she is. Now where did she put the shoes?"

"Tank of the second toilet," Myrtle said cheerily.

Sherlock stepped into the cubicle immediately and tapped the top of the cistern with his wand. At first nothing happened, but then he made a complicated movement with his wand and the top of the cistern flew off, clattering to the floor. "Here we are."

He reached into the tank and pulled out two white, blue and brown trainers that seemed absurdly large to have belonged to a first-year student.

"Are you sure they were his?" John asked as Sherlock handed them to him.

"I think I'll find out soon enough," he answered, clearly delighted. "Oh, this is marvellous. Remind me to tell Mycroft to send Luna Lovegood a copy of the report on the discovery of that bug they found in Indonesia that everyone thought was a myth."

He walked out without another look at Moaning Myrtle.

"Er, thanks again," John said to her.

"Thank _you_ for the image," she answered. "I'll be imagining you two for years to come... Make up whole stories..."

"Yes, right, goodbye." John slammed the door behind him as he hurried to follow Sherlock.


	4. How it was Done

Sherlock had to do a double take as he spotted John in the corner of his eye. Had he learned to Apparate already? How could Sherlock not have heard the Alchemy lab door's loud screech? And why was John here _now_? Wasn't he supposed to be in Transfiguration? It had only been five minutes since Sherlock had set up his experiments. And yet John was holding out a sandwich that looked as though it'd come from the lunch table, rather than one he'd had custom-made by the elves in the kitchen.

"John?" he asked.

"Yes, hello, Earth to Sherlock. I've been trying to get your attention for like ten minutes," John said, ridiculously. He couldn't have done that if Sherlock hadn't been here yet ten minutes ago. But maybe, just maybe, the sandwich meant that Sherlock's estimation of the time was a little off.

"How's it going?" John asked.

Sherlock shrugged. "Still busy."

"I brought you something to eat," John said, "since it looked like you weren't going to show up for lunch."

Or perhaps it had _actually_ been two hours. "I don't have time for food, John," Sherlock said, transferring a few drops of Armadillo bile to a plate, which started sizzling.

John sighed. "Of course you don't. I'll just leave it here then."

"Yes, fine."

"Is there anything I can do? Any way at all I can help?"

Sherlock shrugged. "I have to identify whatever curse, spell or potion meant Carl Powers' end. You have no knowledge of Alchemy, so I doubt you'll be any use."

"Right. Won't there be a lesson in this lab?"

"Not today," Sherlock said. "And even if Professor Bell discovers I'm working here, I doubt she'd do anything but encourage me."

"Okay. I'll just head to Charms then."

This earned a huff from Sherlock. "Charms again."

"Well, I do have a thing or two to learn if a pair of shoes is charming you more than me," John said.

"Not the shoes," Sherlock said, rolling his eyes as he turned to the extract of cut shoelaces he had made and picked up a clean pipette. "The murderer. The fact that, if my theory is correct, they actually _want_ me to get into this. The way they provide a distraction and must be hoping that I in turn relieve their boredom."

John let out a strange sort of snort. "I hope you'll be very happy together."

By the time Sherlock could spare enough attention to look up at him, the solutions safely bubbling in a test tube, John was gone.

...

"Oh, I'm sorry."

Sherlock didn't turn away from the piece of parchment he'd put in a small glass tank. There was no doubt as to who would greet people with an apology.

"I only wanted to practise a little," Molly Hooper babbled. "I didn't get the hang of those symphonic metallisations and I thought the lab would be empty... But if you need the space, I'll just be out of your way."

"It's fine," Sherlock said, still following the blots on the parchment with the tip of his wand. "I think I've almost got what I need."

"Okay. But don't leave because I'm here," Molly said. "I didn't mean to chase you out."

Now Sherlock did look up for a moment, raising an eyebrow at the Ravenclaw. "Do you think you'd manage?"

She blushed. "Probably not."

For a moment she was quiet, putting down her bag and taking out some dusty books, while Sherlock waited for the fluid to reach the end line on the parchment.

"That's not homework, is it?" she asked when she'd turned back to him. Clearly she still hadn't learned her lesson about making conversation.

"Great observation, Molly," Sherlock sneered. "You're improving in leaps."

"Some personal project then?"

"I suppose you could call it that."

"Anything I can do?"

"Some silence would be marvellous." He opened the glass tank and plucked the parchment out of it, then put it down and dried it with a wave of his wand. A forceful tap made the blots light up. "Ha!"

Molly smiled, apparently not impressed by his request for quiet. "Found what you were looking for?"

"Obviously. I just need to confirm..." He turned away from her and tuned her out as he filled a few more test tubes. "Gotcha," he whispered when they got all the right colours.

Molly had, apparently, still not started on her own experiments and was now reading the labels on the mass of bottles Sherlock had stalled out on the nearest table.

"Are you doing an analysis on a Sopophorous plant?" she asked as she had read the ones closest to Sherlock.

"You're wasting your time here," Sherlock answered.

"Oh." Molly faltered. "Sorry, I told you I could go..."

"No, I don't really mind that you're here, especially if you'd be doing your own work in silence," Sherlock clarified. "But you don't _need_ to be here. Your understanding of symphonic metallisations is already better than anyone else in our class's."

And she was blushing again. Why did she keep doing that?

"That's... that's actually nice of you to say," she said. "But it's not quite true, is it? I mean, _you_ 're in our class."

"I wasn't counting myself in 'anyone _else'_." Sherlock picked up the remains of the shoe sole and scraped the tip of his wand over it, then studied it.

"I like Alchemy," Molly said, as though she needed to defend herself in any way. "I don't feel like I'm good enough, but... if I keep trying, I think I'll figure out the bits that aren't clear."

"Well, don't let me hold you up," Sherlock said, finally satisfied and wiping his wand. "I'm finished here. Be a dear and put these bottles back in place, will you? I can never quite remember their places and I know you're brilliant at that."

"They're on the shelves in alphabetical order," Molly pointed out.

"Exactly." Sherlock gave her the smile he knew she reacted best to, then gathered his belongings and left.

...

A lot of people were leaving the Great Hall as Sherlock was heading for his common room. It was dark outside, so that must mean dinner was just finished. Once again, he'd been working for longer than he thought. But it had been worth it. Thirty-two hours after finding the shoes, he had the definite answer that no one had found in six and a half years. He couldn't wait to tell John. And they'd have to make plans; knowing the answer was one thing, but there had to be a way to contact JM and preferably meet them in person. They'd find out whether it was indeed boredom that drove JM into sending Sherlock clues, get the answers that really mattered and then they'd get rid of the threat.

It was rather inconvenient, really, that John didn't show up between the throngs of students. Or that he hadn't come to meet Sherlock at the lab after his lessons. He had been there around noon, of course, Sherlock remembered vaguely, but at the time he had been too busy. And then John's words echoed through his mind.

' _I hope you'll be very happy together._ ' The short sentence bothered Sherlock more than he could explain. Maybe it was the tone in which John had said it. It had sounded so... resigned. As though he knew he couldn't expect anything better than disappointment from Sherlock. As though he had reason to wonder why he put up with his nonsense time and again. And of course Sherlock wondered too, but he'd hoped... He wasn't quite sure what he'd hoped. Surely not that John would be blind to his character. Sherlock knew he wasn't; John was his best friend and the only one who'd really made the effort to get to know him. Even Mike Stamford, who'd been kind to him since their first day at Hogwarts, had quickly produced another volunteer when Sherlock had complained that no one would want to work with him for the Transfiguration project in their first year. Of course he had been grateful for that later, when he'd actually met John Watson, an old friend of Mike's – which was, apparently, the title one earned after having been on a few play dates as little kids. Even as they had been working on that project, John hadn't been afraid to tell Sherlock when his ideas were brilliant, but had also spoken up when Sherlock was going too far – yet another trait that made John different from anyone Sherlock had met before. They'd all put up with him for a day at most and then went off in a huff. It had happened often enough during projects for classes Slytherin didn't share with Hufflepuff. But John had stayed and they'd grown into quite the team.

So yes, Sherlock was certain that John knew him for real, and that made him all the more proud that John chose to be with him anyway. When he had asked him to stay the night after Christmas... It had been a relief. Some sort of proof that John had also recognised all the clues that had told Sherlock months ago that what they had was not a friendship in the way most students defined it. It was something stronger, something beyond the coincidental contact between people who just happened to be in the same classes and decided to make do with each other. And that meant that there was no reason for them to keep the boundaries that were expected in such a friendship.

But it seemed that at least for today, John had had enough of him. Sherlock made a little detour to check the corridor to the Hufflepuff common room, but John wasn't waiting there, nor was he standing near the entrance of the Slytherin common room.

As Sherlock threw his bag onto his bed, he considered visiting the Owlery and sending Wiggins to John to inform him of the plan that had slowly formed on his way here. But he shouldn't. However hard it was, he should probably give John a night without him. Give him time to rest or catch up on his homework. Because if he didn't, he might well be ruining everything. He couldn't let John get tired of him. After finally admitting what he felt for him – sort of – he couldn't lose what they shared. So he'd do this alone. John might not approve anyway. Yes, he liked danger – sometimes it was a wonder why he hadn't ended up in Gryffindor like his sister – but this was something else than breaking a few rules or getting some bruises. This was about the possibility of meeting a wizard or witch who was creative with powerful spells to shape illusions, just to get their threats across. If he were honest, Sherlock didn't want John anywhere near this JM person. He could tell him all about it later. Impress him. Surely that would make him want to help Sherlock again next time.

Nodding to himself, Sherlock grabbed a piece of parchment and scribbled down a note.

' _FOUND! Pair of trainers belonging to Carl Powers (1976-1988). Juice from Sopophorous beans still present. Please collect. The lake. Midnight.'_

He huffed as he reread his words. From the start, he'd had an inkling that some kind of plant would have been involved, complex enough to make identification difficult. If Sprout hadn't been so bloody stubborn, he would have found the solution hours ago.

He put the note down on his night-table and then decided to finally listen to his body and visit the bathroom. Then he'd figure out how to get the note to JM.

But when he returned to the dormitory, the parchment was gone.

...

Without making a sound, Sherlock got out of bed and pulled on his robe and coat, which he'd both laid out earlier so he'd find them in the absolute darkness of the dormitory. For a moment he stood still and listened, but everyone was still asleep, Wilkes making that annoying puffing sound with his lips again. As he softly closed the dormitory door behind him, he saw that there was still some faint light in the common room. A couple of seventh-years were sitting on a leather sofa, working on their Astronomy homework, going by the charts they'd spread out over the low black-wooden table. And in another corner, that annoying Malfoy kid was scribbling away on a piece of parchment – probably a letter to his father. None of them even glanced up as Sherlock crossed the room and went out. As long as you weren't stupid enough to get caught and lose House points, no Slytherin would stop you from going out at night. Many even made a habit of nightly walks on the grounds, simply because they could, or because it helped to clear their minds after hours of stuffy homework. But Sherlock hoped there wouldn't be too many people out and about tonight. If there were, his chances of meeting JM would be considerably smaller.

Once outdoors he buttoned his coat and tied his scarf around his neck. It was freezing, but at least there was no snow to show his marks. Everything was quiet as he walked towards the lake. It was still a few minutes before midnight, but he started walking slowly along the waterside, peering between the bushes, hoping to detect movement.

Suddenly he heard a soft splash behind him in the lake, and he jolted around. A figure had appeared about twenty metres away. Sherlock squinted his eyes and ran closer, then stopped short with a gasp.

"Evening," John said flatly. He was wearing a warm jacket with a fur-lined hood, but his jeans were pulled up and Sherlock suspected he wasn't wearing any shoes, as he stood to his shins in the water.

For a long moment Sherlock couldn't quite believe what he saw. He just stood staring.

"This is a turn-up, isn't it, Sherlock?" John said, just standing there, as though the ice-cold lake wasn't biting at his toes.

"John." Sherlock's voice was hardly more than a whisper. "What in Merlin's name..."

"Bet you never saw _this_ coming." John's voice still had that strangely flat tone. Or maybe Sherlock's brain had simply stopped registering intonation. It seemed to have pretty much stopped all action. How could John be here? Surely he wouldn't have sent the JM messages himself. Sure, the initials weren't too far-fetched; simply turning the M upside-down might have been enough if he wanted to treat Sherlock to a little puzzle. But none of it was John's style. However capable and intelligent Sherlock knew his friend was, he doubted John was able to conjure those illusions. And his fright when the dragon had snapped at him had seemed genuine. He'd often thought that if John were a slightly better liar, it might have saved them some trouble with the teachers, so no. All the facts told him that this wasn't possible.

So what the hell was going on?

A flash of diffuse light appeared from the bushes and in the blink of an eye John was thrown up into the air, further away from Sherlock, floating above a deeper part of the lake. And yet he didn't seem shaken, but simply asked: "What… would you like me… to make him say… next?"

An irrational wave of relief flooded Sherlock's system as he grabbed his wand and pointed it in the direction where the light beam came from.

"Gottle o' geer, gottle o' geer, gottle o' geer," John's voice taunted him.

"Stop it," Sherlock snapped.

"Nice touch, this," John said. "The lake where little Carl died. I stopped him. I can stop John Watson too." The beam moved, dropping John almost a metre down, so his toes hovered just above the lake surface. "Stop his heart."

Sherlock tore his eyes away from John again, trying to quiet down his own panicked breathing. "Who are you?"

Something rustled in the bushes, and another voice answered, soft and with an Irish accent. "I sent you a message. I thought you might get in touch."

From the shadows, a short young man with dark hair and stylish black robes appeared and strolled up to Sherlock.

"I _did_ get in touch," Sherlock said, raising his wand.

"Hmm..." the man said, smirking as he looked at it. "Is that a hard wooden stick you're pointing at me, or are you just pleased to see me?"

Sherlock raised an eyebrow, keeping his wand in place. "Both."

The man finally stopped, mere inches away from the tip of Sherlock's wand, and met his eyes. "Jim Moriarty. Hi!"

Sherlock didn't answer, waiting what the other would do and resisting the urge to turn his head and check if John was alright.

"Oh, don't bother saying anything," Moriarty said. "I already know all about who _you_ are. And yes, I did get your little note. Took you long enough..."

"How?" Sherlock interrupted him.

"You wouldn't want me to ruin the magic by telling you, would you?" Moriarty's eyes gleamed.

There was another sound of movement in the lake, and Sherlock couldn't help looking round. John was still in place, his toes now indeed touching the water. For a moment, Sherlock wondered how the beam could still depart from the bushes while Moriarty was standing right in front of him.

"Don't be silly," Moriarty said, observing his gaze. "Someone else is holding him up there. I don't like leaving my mark." He shrugged. "I've given you a glimpse, Sherlock, just a teensy glimpse of what I've got going on out there in the big bad world. I'm a specialist, you see... Just like you want to be when you grow up." He grinned.

Sherlock frowned in confusion. "I have no recollection of a plan to send people intricate threats or dangle them above lakes."

"Oh, this is much bigger than you and that Hufflepet of yours," Moriarty said. "This is _business_. Everyone's wondering what you're going to do with that odd set of subjects of yours, but you've known all along, haven't you? All the way back since you realised you couldn't become a pirate..."

Sherlock swallowed, once again reduced to staring. No one knew this. Only John knew that he wanted to become a detective, and only his closest family was aware of his pirate phase. It was impossible that this man knew of both.

Moriarty smiled at his baffled expression. "I'm a consulting criminal. Feel free to tell me how brilliant that is. Because you know what: no one ever gets to me, and no one ever will."

"I did," Sherlock said, taking a stronger hold of his wand.

"You've come the closest," Moriarty admitted, "but only because I gave you a hand. I've been dying to meet you, you see. Get a closer look at you." He bent his head a little and licked his lips, looking disturbingly reptilian as he glanced up at Sherlock through his lashes.

"Thank you," Sherlock said drily.

"Oh, I didn't say I appreciate what I see," Moriarty retorted.

"But you do."

"Yeah, okay, I do. But the flirting's over now, Sherlock..." He smirked and his voice rose in pitch as he sing-songed: "Daddy's had enough now!" He stepped even closer to Sherlock, completely ignoring his wand.

"I've shown you what I can do," he continued. "I've sent you those illusions, that little puzzle about Carl, a whole set of Daily Prophet articles just to get you to come out and play." Even though Moriarty was so close, Sherlock couldn't help his eyes flicking to John and back. "So take this as a friendly warning, my dear. Back off. Stay away from those cases you're chasing after every flick through the papers." He smirked. "Although I must admit I'm loving this – this little game of ours. Getting to watch you dance. Hearing about all the naughty things you've been up to with Johnny boy over there... Who thought you'd have it in you?"

"Shut up," Sherlock said between his teeth. "Let... let him go."

"Oh no." Moriarty's smile turned even more malicious. "He'll go the same way Carl went, I think. Just to see what you'll do..."

"I won't let anyone else die," Sherlock growled.

Moriarty's gaze cooled at once. "That's what people DO!" he screamed.

"I will stop you," Sherlock said softly.

"No, you won't." Moriarty's voice was calm again and his expression rather amused.

Sherlock took a deep breath. "What did you do to John?" he demanded.

"Oh, just a little Imperius Curse," Moriarty answered with a shrug. "You should feel him fighting. He's so strong, that sweet little pet of yours. I can see why you like having him around. But then people do get so sentimental about their pets."

"Let him go," Sherlock snarled.

Moriarty let out a laugh. "Are you sure you want that? I don't think he'll come up, you see. The water is ice-cold and none of his limbs will function properly without the right order from me..."

Sherlock glared at him.

"No? Not funny?" Moriarty rolled his eyes. "You're more boring than I expected. But fine..." He clicked his fingers and the beam of light moved John over in Sherlock's direction.

"You can talk now, Johnny-boy," Moriarty said with a nod at John. "Go ahead."

As soon as the spell lifted, John grabbed his wand from his back pocket, pointing it at Moriarty.

"Sherlock, run!" he cried, but Sherlock kept his wand raised, frozen to the spot, unable to even think of leaving John here.

Moriarty laughed in delight. "Good! Very good."

" _Expelliarmus_!" The red beam departed from behind the bushes. John's wand flew out of his hand and he fell to his knees in the water, fortunately close enough to the side that his head didn't go under. He tried to get up so he could look for his wand on the bank, but stumbled and his legs gave way once again.

"John..." Sherlock said, almost begging. They couldn't know what Moriarty was going to do. What whoever was holding the wand behind the bushes was going to do.

"A true Hufflepuff, isn't he?" Moriarty commented, still smiling. "They're so touchingly loyal. But oops!"

Sherlock felt a strong whoosh of air, and suddenly he was dangling in the air right in the spot where John had been floating. Reflexively he kicked his legs, but he was firmly caught up in the beam, and unfortunately still at an angle that he couldn't see who was hidden behind the bushes.

"You've rather shown your hand there, Watson boy..." Moriarty said.

John looked like he was ready to charge the man, never mind his wand or the fact that he was shivering all over, but with a glance at Sherlock he stopped. Sherlock shook his head slightly, hoping he would notice. They couldn't take any more risks.

John held his hands up, though he was still looking around for his wand, clearly preparing for any opportunity.

"Gotcha!" Moriarty sing-songed, looking up at Sherlock like a spider at a tasty prey in its web. "D'you know what happens if you don't leave me alone, Sherlock, to you?"

Sherlock rolled his eyes, hoping his voice didn't shake as he drawled: "Oh, let me guess. I get killed."

Moriarty grimaced. "Kill you? No, don't be obvious. I mean, I'm gonna kill you anyway some day. I don't wanna rush it, though. I'm saving it up for something special. No-no-no-no-no. If you don't stop prying, I'll burn you." He ran his eyes briefly down Sherlock's body, then met his eyes again and his voice became vicious. "I'll burn the _heart_ out of you."

"I have been reliably informed that I don't have one," Sherlock said softly.

Moriarty raised an eyebrow and tilted his head towards John. "But we both know that's not quite true..."

Sherlock blinked, wishing he could feel the ground under his feet, that he was close enough to check on John and to protect him.

"Well, it was _so_ nice to have a proper chat," Moriarty said, smiling.

Sherlock adjusted the aim of his wand. "What if I was to curse you now? Right now?"

"Then you could cherish the look of surprise on my face." Moriarty opened his eyes and mouth wide, mimicking shock, and then grinned. "'Cause I'd be surprised, Sherlock; really I would. And just a _teensy_ bit disappointed. And of course you wouldn't be able to cherish it for very long... You'd drop in the water and John here would be dead right away."

"Isn't that a little disappointing too?" Sherlock asked. "I mean... You can be so inventive. You proved as much with Carl. Putting a Sopophorous bean in someone's shoe... Standing on it must be the perfect way to get the juice flowing, right? And you must have heard that little Carl would step into the water soon, which changes the active substance's structure enough that it's easily absorbed through the skin... He must have fallen asleep within a minute of setting foot in the lake."

Moriarty smirked. "Oh, it wasn't all that hard to come up with. But clever you, seeing through it all. I never liked that kid. A tiny little troll, but oh, he was a _Gryffindor_ , Dumbledore's little favourite! Of _course_ that gave him the right to laugh at me. Well, I stopped him laughing."

Sherlock snorted. "Great way to deal with an annoying eleven-year-old. Seriously, you must be proud of yourself. And I was supposed to, what, admire you?"

"Oh, you do," Moriarty said, smiling. "It's so nice to finally have someone _clever_ around, isn't it? We end up feeling so lonely. Shows, too, if you have to let that little badger lick your toes."

"B-but," John spoke up, his teeth chattering incessantly, "w-why expose yourself like this?"

"Oh, I wouldn't say I'm exposed." Moriarty smiled. "You see, even if I let you walk away from here, what are you going to tell anyone? My name? Good luck proving I exist... I can't be linked to any of my business, definitely not by those incompetent fools who call themselves Magical Law Enforcement or a set of teachers who cling to their subjects like glue."

"So you really just wanted to have a look at me?" Sherlock asked.

"Well, not _just_ ," Moriarty said as though he was admitting a rather big secret. "I also wanted to tell you that you can't be allowed to continue. You just can't. I would try to convince you, but..." He laughed and pitched his voice into that annoying sing-song again. "Everything I have to say has already crossed your mind!"

Clearly the young man was crazy. He did have a point saying that the teachers were idiots, not noticing that one of their students was a dangerous psychopath who'd killed a first-year. But Moriarty was also underestimating him and John. He had come out here because he believed that two students were not capable of stopping him. Sherlock looked down and met John's eyes for a moment, and John gave him a tiny nod.

"Then probably my answer has crossed yours," Sherlock said, and he flicked his wand, thinking ' _Stupefy_!' very loudly. Yet Moriarty had already conjured a shield before the spell could hit him and he laughed. John was looking between them with a clear expression of panic, but the expected flash of green light didn't come from the bushes, and Sherlock and Moriarty just stared at each other, calculating, waiting for the next move. Moriarty smirked, and Sherlock narrowed his eyes, ready.

Then the sound of flapping wings broke his focus. An enormous black owl came zooming through the air, its feathers brushing Sherlock's hair before it landed on Moriarty's shoulder, almost knocking him over.

Moriarty just raised an eyebrow and sighed in exasperation. "D'you mind if I get that?"

Sherlock huffed. "No, no, please. You've got the rest of your life."

Moriarty looked down, unrolling the parchment, but he stepped closer to John as he did so, making sure Sherlock wouldn't have a clear aim.

"Oh," the criminal breathed softly as his eyes had skimmed the letter. "Oh, I hope they know that if they're lying to me, I'll find them and skin them."

Sherlock looked at John in confusion, but it looked like John wasn't really following Moriarty's words anymore. Even in the darkness Sherlock could see how pale he was, just sitting there in the mud without making any attempt to get further away from the icy water.

"Sorry," Moriarty said, reclaiming Sherlock's attention. "Wrong day to die…"

"Oh?" Sherlock asked. "Did you get a better offer?"

Moriarty glanced at the letter, then turned around and started to walk away. "I'll write to you, Sherlock." He clicked the fingers of his free hand and Sherlock was swooped back to the lakeshore. Once he had found his footing, he aimed his wand at Moriarty's back, but both the beam of light and the short man had disappeared, as though they'd never been there.

Sherlock spent a second more checking whether he was really gone, before he turned and ran to John. He stuck his wand in the pocket of his robe and embraced the shorter boy. "All right?"

John just clung to his warmth, his whole body shaking.

"We have to get inside," Sherlock said, pulling back so he could get out of his coat and scarf and wrap John in them. "John, are you alright?"

"F-f-fine…" John managed, and Sherlock cursed himself for asking. Of course he wasn't alright. He was hypothermic, had fallen victim to an Unforgivable Curse and who knew what Moriarty and his assistant had done to him before he'd ended up in the lake. Sherlock helped him to his feet, wrapped an arm around him and urged him towards the castle entrance. As he stepped on something hard, he recognised John's wand and put it in his pocket without even checking if it was damaged. It could wait.

They proceeded slowly but steadily, and once inside, Sherlock started pulling off John's wet clothes.

"I'm fine," John muttered weakly.

Sherlock pulled his jumper over his head and then opened his jeans.

"Sherlock," John protested, but Sherlock wouldn't stop. John would freeze if he did. He needed warm, dry clothing; blankets, a fire, tea. "Sh-sherlock!"

Only as Sherlock looked into John's eyes did he catch up on his own panic.

"Merlin's beard," John whispered, his knees buckling.

Sherlock caught him. "No, don't, the floor's too cold," he chided. "Come on. Please stay upright just a little longer. We'll get you to the Hospital Wing. Madam Pomfrey will give you something to warm you up."

He guided John's hand to the wall so he could keep himself up and had just started pulling his own robes over his head so he could give them to him, when footsteps and an outraged cry sounded.

" _What_ do you think you're doing?"

Sherlock ignored McGonagall and let the Slytherin robe drop over John's head. "If your pants are wet too, you should probably take them off," he muttered, but John was just staring at McGonagall with an expression close to horror.

"Mr Holmes, if you could spare me your attention for a minute, you could explain to me what you are doing out after hours, and why you've just stripped Mr Watson of his garments in the Great Hall!" McGonagall's nostrils were flared, a clear sign that she was about to explode.

"Look, we need to get John to the Hospital Wing," Sherlock said impatiently. "He's been exposed to the cold for Merlin knows how long, with a dive in the lake to top it off."

"A dive in the lake?" McGonagall repeated. "Whatever for?"

"Do you honestly think it's a hobby of his in January?" Sherlock snapped. "Help me move him."

Sherlock was slightly surprised that she actually followed his order, but then again she must have seen the heap of wet clothes by his feet by now, combined with John's blue lips. They each put one of John's arms over their shoulders.

"Sherlock..." John muttered when they'd only taken a few steps, and then his legs gave way and he almost pulled McGonagall with him to the floor.


	5. Many Happy Returns

John was feeling faintly chilly when he woke up. Especially his feet were two lumps of ice, which was odd, considering that he was enveloped in comfortable warmth, the way he would after a restful night with Sherlock by his side. He also couldn't remember going to bed, let alone that Sherlock had been there, and he had the odd feeling that this wasn't his own mattress. The light was all wrong in order to be the Hufflepuff dormitory. But then where was he? And why did he have such a horrible bitter taste in his mouth? His tongue even felt a little burned. Surely Bill hadn't gotten him to try another Scotch bonnet-flavoured Bertie Bott's Bean.

He decided that if he didn't know all these things, it must mean that he needed more sleep, so he snuggled further into Sherlock's warmth, humming as he inhaled his comforting scent. Yet something was off there, too. Sherlock smelled a little... muddy. With something that vaguely reminded John of seaweed. Yet another thing that didn't make sense, because what kind of experiment would cause that smell?

Sherlock's arm tensed around him in reaction to his movements. "John?" he said softly. "John, are you awake?"

Only now did it strike John that he could actually open his eyes to find out more about this mystery. It took some effort, but when he blinked them open he immediately noticed how worried Sherlock was looking.

"Did something happen?" John slurred, a little surprised how rough his own voice sounded.

Sherlock's brow creased, the look in his eyes almost painful to observe. "You... You don't remember?" he asked. "The lake... Moriarty..."

It was as though Sherlock had opened the floodgates to his memory. John actually stopped breathing for a moment as everything hit him at once. Brooding about Sherlock during the lessons, deciding to go see him anyway, strong hands that had dragged him into a corridor, a purple spell hitting him. Waking up outdoors without control over his own mind. Struggling against the boundaries of an Imperius Curse, knowing he should be able to throw it off, but never managing to break through. Sherlock's face when he spotted him floating above the lake. Hitting the ice cold water. Losing his wand and just sitting there, unable to save Sherlock, unable to fight.

A shiver that had nothing to do with being cold went through his whole body.

"I... I do," he managed, tangling his hands in Sherlock's shirt. "Remember."

"He's gone now," Sherlock said, stroking his palms over John's back as he held him close. "He disappeared when that black owl arrived."

John nodded. "I know. I saw. I just couldn't... I couldn't..." His breathing was picking up and he felt he was losing it very quickly. But the pattern of Sherlock's fingers on his soft jumper – which someone must have fetched or summoned from his trunk – gave him something to focus on, and after a long silence he felt himself calm down enough to tilt back his head so he could look at Sherlock, just holding him rather than clinging to him. "Are you okay?" he asked.

"Me?" Sherlock looked like he hadn't even contemplated how he was feeling. "Yeah, I'm fine. I'm fine." He swallowed. "Fine."

"He didn't hurt you?" John insisted.

"No. I just... I'm glad you're awake again."

John nodded. "I can't remember how I got here."

"You passed out," Sherlock said. "McGonagall helped to bring you here and Madam Pomfrey's been working to warm you up ever since. Pepperup Potion, warm dry clothes, and so on. I felt it would be... efficient... to provide body heat as well."

John smiled. "I appreciate that."

"McGonagall is off to find Dumbledore now," Sherlock continued. "We'll probably have to give some kind of statement. She actually ordered me to go to his office, but..." He frowned.

John hugged him closer again, understanding. He'd feel the same if it had been Sherlock who suddenly passed out on him after what they'd just gone through.

"I, er..." Sherlock said after a moment. "I just wanted to say... That, that thing you offered to do. By the lake. That was good..."

John sighed at the memory. "It was pathetic," he said. "I bet they only let me keep my wand for something like that. Just to show us how helpless we really were."

"It didn't feel helpless to me," Sherlock said earnestly.

"All it did was get you in more danger," John said. "I'm sorry."

"I'm the one who should apologise," Sherlock muttered, and John stared at him.

"What?"

"Well..." A weak shimmer of the usual mischievous glint appeared in Sherlock's eyes. "I said I should, not that I did..."

John giggled, relaxing a little. "Of course."

"Did they..." Sherlock cleared his throat. "Did they do something before I arrived? Moriarty and... his assistant...?"

John shook his head. "I was unconscious most of the time. They didn't hurt me. Just revived me and put me under the curse right away. It was... Well, awful."

"And did you see his assistant?" Sherlock asked.

"No. It must have been someone pretty strong, but... that's all I know. I should... I should probably have paid more attention..."

"No, John, please." Sherlock stroked his cheek in an uncharacteristically tender motion. "There is no way in which you should blame yourself for this."

"Mr Holmes," Madam Pomfrey hissed, startling John, who hadn't noticed that she'd walked up to his bed. " _What_ are you doing in Mr Watson's bed? He's recovering from a severe trauma, he needs rest!"

Sherlock rolled his eyes and sat up. "I'm providing body heat. It is the most efficient way to warm him, especially combined with your potion, as you should actually know, considering your function here."

Madam Pomfrey inhaled sharply, a retort ready on her lips, but John held up a hand to stop her. "Please," he said. "I really don't mind. It's comforting that he's here. I feel safer."

The matron deflated. "I shouldn't allow students to share a bed," she pointed out.

"What, do you think I'm going to jump John in the state he's in?" Sherlock asked bluntly. "Honestly, what is it with you staff?"

Madam Pomfrey was pressing her lips together in indignation, but the door to the Hospital Wing swung open, distracting her.

Professor McGonagall was followed by Professor Sprout, Professor Snape and Professor Dumbledore. Sherlock quickly slipped out of the bed, and even though he still stood very close, another shiver went through John's body.

"Excuse me, but this is unacceptable!" Madam Pomfrey protested. "This is a Hospital Wing, not a meeting room. My patient needs rest!"

"It's my fault," Sherlock said. "They believe I need to have a word with the headmaster, but I refuse to leave John's side." He looked down at John. "I hope you don't mind..."

"Definitely not," John said, trying not to give in to the urge to rest his head against Sherlock's thigh. "I think I should follow this conversation, and well, I'm lying down. It's not going to wear me out."

Madam Pomfrey looked highly sceptical at that, but she moved aside so the teachers and headmaster could surround the bed.

"Good to see you awake, Mr Watson," Professor McGonagall remarked.

"You two are such enormous idiots," Professor Sprout scolded. "Why didn't you call in our help? Why do you two absolutely want to prove that you can handle it all on your own? Are you that addicted to danger?"

Sherlock huffed. "John isn't to blame this time. He wasn't proving anything, he was kidnapped from under your very eyes, in a corridor of this very castle. If you all can't prevent _that_ , do you think you'd have been any good out there by the lake?"

"Sherlock," John muttered.

Sherlock crossed his arms, staring the teachers down.

"I understand that you're angry because your friend got hurt," Professor Dumbledore said calmly, "but I believe it would be more productive if you tell us everything that happened rather than snapping at us. We are now aware that you blame us for the unfortunate events of the evening, so let us move on."

"Does _everyone_ need to hear it?" Sherlock asked, pointedly avoiding Professor Snape's gaze.

"Yes," Professor Dumbledore said. "The Heads of your Houses should be aware that you are being threatened, and after the fright you gave Professor McGonagall, I think it is no more than fair that her curiosity is satisfied as well."

Sherlock sighed and started talking. John felt he should pay attention so he could add the necessary facts, but somehow it was very hard to keep focusing on the words. And he hadn't even seen his attacker, so he didn't know more than Sherlock.

Only registering the comforting tones of Sherlock's voice, he'd almost gone back to sleep when Professor Sprout asked: "But why didn't you tell any of us that you were reaching out to JM?"

"Aside from the fact that you thought I was exaggerating when I _did_ come to you..." Sherlock gave her a pointed look before he continued. "That man somehow knew that I'd found his message in the dragon smuggling articles even before I'd sent an owl to the Ministry. He'd know if I'd told you about my plan, too. He wouldn't have shown up and all my work identifying the Sopophorous bean juice in Carl Powers' shoe would have been for nothing."

John glanced up at Sherlock, wondering if he'd even _thought_ of informing the teachers tonight. He seriously doubted it.

"It would never have been for nothing," Professor McGonagall said, sounding a little choked up. "It answers the question that both Carl's family and we teachers have long asked ourselves: how such an accident could have happened. The fact that it was not an accident, and that an actual _murder_ could happen, as you would put it, right under our noses, gives us all the more reason to try and protect you."

"The easiest way to protect us is by making sure that Moriarty is caught," Sherlock said. "In other words, by letting me help during the investigation. Do you know yet how he got on the grounds? He couldn't have Apparated, so he must have used a secret tunnel or something..."

"None of our intruder alerts have been activated, but we are looking into the matter," Professor Dumbledore answered.

"What is worrying us more, is that there is no Jim Moriarty in our student records," Professor Sprout said. "According to what you told us, he knows the castle quite well, and he had the chance to put a bean in Carl's shoe, so he must have been a student."

Sherlock nodded. "He did warn me that I'd have a hard time proving he existed."

"And when that owl arrived, he just left?" Professor McGonagall asked. "Did you recognise the owl?"

"No. I have no idea whose it is. It was quite large, and black, or at least a very dark colour." Sherlock shrugged.

"Well, I suppose that is enough mystery for one night," Professor Dumbledore remarked. "We should leave Mr Watson to Madam Pomfrey's good care. But Mr Holmes..."

Sherlock made himself a little taller as he looked up at him, and for a moment John was afraid that the headmaster would send his friend out.

"If anything else happens, any kind of suspicious messages or letters arrive, or another clever plan takes shape in your mind – please let us know. If only because it's in your own and Mr Watson's best interest."

Sherlock studied the old, bearded face for a moment, and then nodded. "I will."

"Thank you." Professor Dumbledore turned to lead the teachers out of the Hospital Wing, but then Sherlock stopped him. "Professor Dumbledore?"

"Yes, Mr Holmes?"

"I know you will probably send a letter to my parents about what happened. However, I believe it's unnecessary to startle them. Might I ask you to send the letter to my brother Mycroft instead? He can in turn tell them everything he deems necessary."

"Of course," Professor Dumbledore answered. "Goodnight, Mr Holmes, Mr Watson, Poppy."

As soon as they were all gone, Sherlock got back in bed with John. Madam Pomfrey saw, but she just let out a soft huff and left them alone.

"Why did you make him write to Mycroft?" John asked Sherlock, a little confused that he would reach out to his brother of his own free will.

Sherlock smiled. "As I said... Dumbledore would write to our parents anyway and that would earn us nothing – except worried words in reply. But Mycroft might actually provide us with answers. He'll have to realise that we are involved in this case, whether he likes it or not, so he can give us more data."

John nodded. "Clever." He was quiet for a moment. "What do you think Moriarty's next move will be?"

"I don't know," Sherlock said. "He does seem rather the unpredictable type. We'll just have to wait."

John sighed and snuggled into Sherlock's warmth again. He could _feel_ him thinking, and he wished he'd speak his mind rather than needing to deal with it on his own, but he was just so tired. However, just before he could drift off, a thought struck him that made him sit up with a jolt.

"Sherlock, it's your birthday!"

"Huh?" Sherlock looked up at him.

"It's been your birthday for over two hours and I just didn't think about it!"

Sherlock snorted. "Yes, it wasn't like you had something else on your mind. I'm hardly going to blame you for forgetting it when something much more important was going on, John. You know I never really celebrate it anyway."

"But you're turning seventeen!" John protested. "That _is_ important." He lay back down again and kissed Sherlock's lips. "Happy birthday."

"I suppose it _is_ convenient that I'm of age now," Sherlock admitted. "But I'm much happier that you are safe."

John smiled and kissed him again, and Sherlock held him close, deepening the kiss.

"Goodnight, John," he mumbled when he finally pulled back, and John, feeling much warmer now, was asleep within minutes.

...

He was floating. Or at least he felt like his feet weren't quite touching the ground. And perhaps that was for the best, because as he walked on, the steady floor was replaced by a pile of bottles, and even though he felt so light, he couldn't keep his balance.

"Dance!" a voice said behind him, and as he turned he recognised his sister, Harry, but then she was out of view again, for his feet were swaying him from to side to side and pirouette to pirouette, and he felt absolutely ridiculous, but he couldn't stop.

"Not a trace of control," his mother complained. "He's going to end up just like you."

"I'm not!" John wanted to shout. "I can break free of this!"

But his mouth wouldn't open and his limbs continued moving as though he was being attacked by a swarm of wasps.

Now another voice, very vaguely familiar, was mocking him. "Look at that, our hero. How's he going to help anyone, then?"

"At least like this he does exactly what we want him to do," his mother answered. "He'll finally be some help."

"Go on, Johnny boy." For one awful moment, his sister was wearing Moriarty's face. "Make us proud for once."

"Or else..." His mother pointed up and for a moment John's limbs forgot about the dancing. Sherlock was standing on an old-fashioned watch-tower, close to the edge of the platform.

"No!" John begged. "Stop!"

But his mother and sister laughed, and Sherlock stepped into the void.

"SHERLOCK!"

"John. John!"

Now they'd added shaking him to the dancing, but John didn't care, he couldn't breathe anyway...

"John!" Sherlock's voice became more urgent, and finally John's eyes snapped open. Sherlock was safe. He had survived.

"Come on, John, look at me. It was a nightmare. You're in the Hospital Wing at Hogwarts. We've had a bit of a rough night but we're both alright. Please, just – _breathe_."

And John gasped for air, but the way he obeyed the order made him panic again. He still wasn't in control. He was still doing what they told him to. He was still under the Curse...

With a small sound he took another mouthful of air, but it was like his lungs had forgotten all about oxygen exchange.

Sherlock threw back the covers and supported him with one arm. "Come on, sit up. That's it. Now take a deep breath. Blow out the air. That's it, we're safe, it's alright..." He laid a hand on John's shoulder, but apart from that, he kept his distance, giving John space and deepening his own breath so John could follow its rhythm. As he grew more awake, John realised what Sherlock was doing and felt more comfortable listening to him, but he was still out of breath, trembling and wiping tears from his eyes.

"'m sorry," he managed finally, and Sherlock raised an eyebrow.

"Because obviously you had a panic attack on purpose. Don't be an idiot, John. You have no reason at all to apologise."

John let out a shivering breath and leaned into Sherlock's chest. Sherlock's arms immediately enveloped him in a protective hug.

"Alright?"

John nodded, wishing he could hide from the images in his mind.

"Do you want to talk about it?"

"No," John whispered. "Please, no."

"Okay."

They just sat like that until John's breathing had normalised, and then Sherlock carefully lowered him onto the mattress again, never letting go.

"Should I get you something? Water? My violin?"

"It's fine," John said. "Please stay."

"Alright." He kissed John's forehead. "Try to sleep some more. I'll wake you when you get restless."

"You're... You're sure the curse broke, right?" John looked into his eyes and swallowed. "That I'm not under the Imperius anymore, that he can't make me hurt you?"

"I am," Sherlock said. "You are John Watson and you do what you want." He smiled a little.

"Okay." Once again, John hid in his arms, but it was a long time before he dared to close his eyes.

...

When Madam Pomfrey woke him up in the morning, he was knackered. It didn't help that Sherlock had disappeared, but he didn't dare ask the nurse if she'd sent him out, so he quietly ate his breakfast and let her check his temperature and his eyes.

"That seems alright," she muttered, but she did give him another potion.

"What is this?" John asked, frowning.

"Something to put your nerves at ease," she answered. "It should help with the flashbacks."

"I don't have flashbacks," John said, but she just gave him a look.

"It won't do you any harm, John," Sherlock's voice sounded from the door opening. John couldn't help a sigh of relief at the sight of him.

"Sorry I wasn't here when you woke up." Sherlock sat down at the foot of his bed and held up a letter. "I expected an owl and they're not allowed in here."

"Rightfully so!" Madam Pomfrey said, still watching John, so he decided to drain the potion.

"Could you give us a moment?" Sherlock asked her when John had returned the empty flask to her.

She left with an eye roll and a huff.

"She just wants to make herself useful," Sherlock told John. "She came to have a look last night because you'd been shouting, but I made clear I could handle it. I did need to calm you down a couple of times more, but I doubt you woke up enough to remember."

John winced. He didn't want to think about his nightmares or the events that had caused them.

"Mycroft answered," Sherlock continued quickly, studying John's face. "I'd like to read the letter out to you so I can hear all the facts for myself."

"Go ahead," John said.

Sherlock folded his legs under himself, facing John, and started reading:

" _Dear brother,_

 _Many happy returns._

 _It is a relief to read that you are unharmed after your little adventure. There will be no need for me to tell you that you are growing into a true security nightmare – I imagine that will only encourage you, as always ignoring my worries. However, as my earlier approach of withholding information failed to keep you safe, I will learn from my mistakes and send you the results of our interrogations of Kitty Riley as a birthday present._

 _The hidden messages in her Daily Prophet articles came as a surprise to her. Ms Riley insisted that she had used different words in her submitted drafts, but the Prophet's editors stated that only the smallest of changes were made in those short reports, none of them concerning the contents. A quick check of their profiles makes us believe that the Prophet staff is not involved in the matter, but we realise that Moriarty must be a master of disguise and manipulation, so we are investigating further._

 _As the interrogations proceeded, Ms Riley admitted that she had more information for us. She said to have come onto the trail of the dragon smuggling gang, and after giving us some names, the Auror department made the connection to their leader, General Shan, quickly enough. They had had their eyes on her for a long time, but never found enough proof, and this was enough to bring her in for questioning._

 _As she was being charged not only for smuggling, but also for criminal conspiracy, fraud and multiple murders, Shan soon realised that it was in her best interest to cooperate. Thus it turned out that she had not organised all of her syndicate's activities on her own. She had received tips, bits of information which made it easier for her to apply pressure on the right people and which told her the time and place in which her thievery would be most successful. Obviously we asked for this helpful source's name, but here her answers were increasingly vague. According to her, there had never been any real contact, only messages. Whispers. A name everyone knows but no one speaks. The notes are only signed with "M"._

 _At this point in my narrative, I must admit to you that I might have written anyway, for disaster struck not only at Hogwarts, but also here at the Ministry. Yesterday afternoon, mere hours after General Shan had been served lunch in the holding cells under the Ministry where she awaited her trial, during the busy hours in broad daylight, her body was found. It was clear that she had been murdered, but no one had spotted the perpetrator. Obviously, suspicion falls on Moriarty, who must have felt that he was getting too close to the firing line. You'll understand that we are having a field day analysing and improving security here at the Ministry. Either Moriarty has found a very efficient way to surpass all sorts of restrictions and identifications, or he has people that are successfully infiltrated both at Hogwarts and at the Ministry of Magic._

 _On that matter, I am also discreetly looking into the Ministry's own security measures for Hogwarts, for any traces that can lead to Moriarty's true identity. We must assume that he has help from the inside. Therefore I must ask you to be careful whom you trust. And as we cannot be certain that a second encounter would end as well as last night's, I ask you once again not to leave the castle at night._

 _Congratulations with your coming of age, little brother, and give my best to John._

 _MH_

John blinked. "Someone actually _died_? At the Ministry?"

"Yes," Sherlock said. "That _is_ quite interesting..."

"No, Sherlock, don't you see what that means?" John sat up straighter so he could lean into his friend. "Mycroft said that it's 'a name no one speaks'. Doesn't that ring any bells with you? Someone who makes people afraid of his name and becomes powerful enough to commit murder at the very heart of Magical Law Enforcement? Or did you seriously delete _that_ part of history?"

"I didn't," Sherlock said, his expression softening a little as he reached out to take John's hand. "I'm sorry, John. I didn't think of how it must sound to you."

"It's fine," John said, though he wasn't quite sure he meant it.

"If it can reassure you, I think those two points are the only way in which Moriarty compares to... You-Know-Who."

"That's more than enough if you ask me," John muttered.

"I do not know what exactly Moriarty's purpose is, but so far, it looks like he's only causing trouble for the sake of it," Sherlock said. "There is no twisted ideology behind his actions. In some ways, that might make him more organised and thus more dangerous, but on the other hand, his followers must simply be employees, bought with money, rather than believers in theories that may cost many lives."

"So fewer families may be fucked up," John concluded. "I suppose that is something of a reassurance..."

Sherlock squeezed his hand. "Moriarty is at the centre of all this – whatever it is. If we get to him, we get to all of them. It will mean the end of his network. All we need to do is make sure that he doesn't get the time to do any more damage."

"As if that'll be simple," John sighed.

"It'll be... challenging." Sherlock shifted to his knees and hugged John. "Are you alright?"

"Okay," John answered, pressing his face into Sherlock's neck and trying not to think at all.

Madam Pomfrey's footsteps approached and Sherlock quickly let go of him.

"If you could spare me a minute now, Mr Watson," she said, "I wanted to tell you that if you feel well enough, you may leave the Hospital Wing today. There isn't much more that I can do for you here, but of course you shouldn't hesitate to return if there are any other complaints."

"Oh," John said, slightly surprised. Spending the night here had reminded him so much of the time he'd had to stay here for over a week due to his Quidditch injury, that he hadn't expected his discharge so soon. "That's great. Thank you."

"You should take the day off, though," Sherlock said. "You're still a bit... shaken."

John raised his eyebrows. "And how's it going to help if I just sit at my dormitory, thinking it all over? I have a full day of lessons today. It'll only stress me out if I have to catch them up later."

Sherlock frowned. "I can pass you my notes for Defence of the Dark Arts and Herbology, and Mike will have your back for Transfiguration and Charms. I don't see the problem."

"Well, I do." John sighed. "I really don't want to sit still now if I don't have to. The distraction will do me good."

"Fine. Then I'll come with you."

"What?"

"That might actually be a good idea," Madam Pomfrey said, nodding in approval. "It's quite a shock, having been under the Imperius Curse, so it wouldn't do to be alone in the next couple of days."

"But I wouldn't be alone, would I? There's a whole class with me," John protested.

"A class that, for all we know, may hold Moriarty's assistant," Sherlock said.

"But it also holds Bill and Mike," John said. "They won't just let anyone kill me, you know. You've got your own work. You wouldn't want to miss Arithmancy."

Sherlock huffed. "I can perfectly learn the lesson on my own."

"But you shouldn't," John pointed out.

"Then I'll just come to Transfiguration. I'm sure it's fine with McGonagall if I want to learn more."

"Sherlock... I know you haven't slept at all. You should get some rest too, see to your own homework... You can't worry about me all the time."

"That's true, too," Madam Pomfrey said. "If Mr Watson feels safe enough to go, I suppose I should encourage that. Returning to normal life as soon as possible can be effective to minimise the trauma."

"Ha." John gave Sherlock a triumphant look.

"Fine," Sherlock muttered. "I _will_ come and check on you between lessons, though."

John smiled. "Thank you."

...

"John!" Bill Murray almost knocked him over as he ran to him in the corridor to the Transfiguration classroom. "John, is it true?"

"That depends what kind of rumour you've heard this time," John answered, smirking a little.

"Oh, obviously I'm talking about your and Sherlock's impending marriage." Bill rolled his eyes. "Seriously, what happened last night?"

Most of their classmates had come to stand around them now, equally curious.

"Well... To be honest I don't remember all of it..." John took a deep breath, resigned to telling them a short version of the events.

"Damn, John," Bill cursed when he was done talking. "I should have told someone when you didn't show up in the library. I just thought you'd gone and found your Slytherin..."

"I _was_ on my way to him," John said. "It's really not your fault, Bill."

"I know. I just... Fuck. We could have lost you... The finest Beater Hufflepuff has ever had." His weak smile betrayed that he was more shaken than he wanted to let on.

"But I'm fine," John said, patting his shoulder. "Alive and kicking."

"And zealous!" Mary Morstan, a Slytherin who followed all the same classes as John and Mike because she also wanted to become a Healer, added. "If I'd been under an Unforgivable Curse, I sure as hell would take the excuse to get out of my classes for a couple of days."

John chuckled. "What can I say? The Hat wasn't mistaken when it put me in Hufflepuff."


	6. Life Goes On

"I'm going to the library," Sherlock said as they left Greenhouse Six that afternoon.

"Nope," John said.

"What?"

"You're not." John grinned at the look of confusion on Sherlock's face. "You're coming with me."

Sherlock frowned. "Is something wrong? Only this morning you assured me you were feeling well enough to attend your lessons without me. And you've been rather cheerful all day, considering what you've gone through." He paused, lips pursed in thought. "Perhaps it is the dusk, reminding you of the moment when you lost consciousness and making you feel less safe. However, John, I assure you..."

"Could you shut up for a moment?" John asked, amused. "It's touching how worried you are about my well-being, but I really _am_ fine. You just have somewhere else to go."

"Oh?" Sherlock gave him a searching look. "And wherever might that be?"

"My common room," John said.

"So... you do want my company?" Sherlock asked.

"Do I ever _not_ want your company?" John rolled his eyes. "This isn't about me. It's about the party."

" _What_ party?" Sherlock looked like John had gone crazy. "John, you know perfectly well I don't do _parties_..."

"Yeah, except when they're celebrating your own birthday."

"You... I..." Sherlock was sputtering in indignation. "I don't celebrate my birthday!"

"Well, you do now!"

Sherlock groaned loudly. "John... Please don't tell me there will be other people. Or music. Or _dancing_ , for heaven's sake. I need to do research, find out who Moriarty is and how we can get to him..."

John sighed, slightly disappointed, but to be fair he had known Sherlock wouldn't be as delighted at the prospect of a party as he was. "You can't let that man ruin your seventeenth birthday, Sherlock. Or any other day."

"I'm not planning to let him do that," Sherlock countered. "That's why I want to stop him as soon as possible."

"I... I get that," John said, taking Sherlock's hand. "And I agree, really, but... They'll all be coming down to the common room anyway. I invited them days ago and... I didn't feel like blowing it all off, so..."

"It's fine," Sherlock said, but then he frowned again. "They'll _all_ be coming? Who will?"

John shrugged. "All your friends?"

"My _friends_?" Sherlock repeated. "So it'll be just you after all?"

"Don't be an idiot," John said, rolling his eyes.

The Hufflepuff common room was in fact rather crowded when they entered. And it became even more so after a few minutes, when Bill let in a bunch of people from the other Houses.

"Happy birthday!" he told Sherlock, a skip in his step as he walked over and grinned widely. "Brilliant plan of John to adopt you as a Hufflepuff. We haven't had a proper birthday party in a month or more!"

Sherlock snorted. "So glad to be of use."

"We better go fetch the food, though, John," Bill said. "Before they start eating first-years..."

"Coming!" John stood up and, feeling exuberant, dropped a kiss on Sherlock's hair. "I'll be right back."

"I'd hope you weren't planning to leave me here," Sherlock replied, actually looking a little afraid at the throng of people.

When John, Bill and Mike returned from the kitchen with their arms full of nibbles, cakes and bottles of pumpkin juice, a dark-haired girl was talking animatedly with Sherlock. As soon as everything stood on the tables – which were attacked immediately – John wormed his way past some Gryffindor Quidditch players and back to Sherlock, holding a plate.

"Got you a bit of that chocolate cake you love," he said, beaming at Sherlock as he handed it to him.

"Oh. Thank you." Sherlock smiled at him and John felt slightly giddy. He really did want to make this a memorable day for Sherlock, in spite of threats and fears. He deserved it.

The dark-haired girl cleared her throat.

"Right," John said, looking up from Sherlock. "Who are you, then? Did we actually invite you?"

She laughed. "Oh, you wouldn't want to miss _me_ at a party. Irene Adler." She held out an elegant hand for John to shake.

"John Watson. Nice to meet you," John said.

"She's in Slytherin, the year above us," Sherlock explained.

"I took the liberty of bringing Kate, my girlfriend," Irene said, reaching out and somehow pulling a blonde, taller girl from the crowd. "I believe you have met."

John nodded at the Slytherin Chaser. "Sorry about that Bludger last year."

"Don't worry about it," Kate said, smiling. "It's part of the game. And I'm _all_ for games." She winked at Irene and John felt he should look away from them very quickly.

"Well... I'm dying to check out those almond cakes," Irene said. "Congratulations, Sherlock." She leaned over Sherlock's chair and landed two resounding kisses on his cheeks, leaving John to stare at her in shock.

"Wow, boys," a voice said behind him when Irene and Kate had turned to the food table, and John still hadn't remembered how to close his mouth. "I didn't know you were into all that."

Mary Morstan joined them with a very... evil... grin.

"Into what?" John asked.

"You know... Irene..." She giggled. "I'm not judging you, but it is a tad unexpected."

"I have no idea what you are talking about," John said.

"No?" Mary said. "Oh... I thought people outside of Slytherin knew about her too. She provides a rather... unusual... kind of entertainment. For those who lust after... pain... power plays... all that kind of stuff."

Not only did John's mouth return to its open state, it also felt like his eyes were going to roll out of his head. "She... You're kidding, aren't you?"

"She isn't," Sherlock said, his face frustratingly expressionless.

"But... how... She can't possibly do that here at Hogwarts!"

Mary snorted. "What, because the teachers would notice? Don't be silly, John. Apparently there are rooms in the castle that are well-known for this kind of thing among the oldest students."

"But... She has a girlfriend!" John protested.

"And they are in an open relationship." Mary rolled her eyes. "Really, Sherlock, how can you stand him? Happy birthday, by the way."

"Thanks. I don't know, sometimes." Sherlock smiled up at John and actually winked.

"But... No, I'm not getting over this," John said. "They have _sex_? At Hogwarts?"

"I had no idea you were so innocent," Mary said, clearly delighted. "Poor Sherlock..."

"What better place for her business than a school full of sexually frustrated teenagers, willing to experiment?" Sherlock pointed out. "She must earn quite a lot of money."

"She's _paid_ for it?" John cried out, and then realised that maybe he should keep his voice down if he didn't want Irene to hear him.

"Oh, and not just in money," Mary said. "It's really quite brilliant. I mean, I wouldn't want to do it myself, but I sure admire the idea. The things she must know..."

"Know?" John repeated, starting to get a little annoyed how he seemed to be behind on this whole conversation.

"Well, yes," Mary said. "She knows what everyone likes. And she's probably come across quite a lot of other secrets that way... And think about the blackmail possibilities."

John raised an eyebrow at her. "So that's something you find admirable."

"It's _clever_ ," Mary insisted.

"It is, isn't it?" Sherlock said, sounding rather absent and looking over to where Irene was laughing at something Bill Murray had just said. John had the odd urge to drag Bill away from her and inform him how dangerous she was. But maybe he was actually up for a bit of that sort of danger. And this _really_ wasn't a train of thought John wanted to follow about one of his friends, so instead he focused on Sherlock.

"You're looking far too interested," he informed him.

"Hmm."

"There are _pancakes_!" Mary suddenly exclaimed, and before John knew it, she had disappeared, leaving him with a non-responsive Sherlock.

Knowing that it wasn't much use hanging around if Sherlock was in such a mood, John decided to find other company as well and joined a group of his Quidditch mates.

"Everything alright with him?" Greg Lestrade, the seventh-year Gryffindor Keeper, asked, nodding towards Sherlock.

"Yeah," John said. "I think he just had an idea and I'm not sure I want to know."

The Gryffindor captain, Sebastian Moran, chuckled and a third-year girl, who came by with an almond cake in her hand, actually stopped to look up at his muscled form with large, terrified eyes, which made John laugh too.

"Don't worry, he's not going to bite," John told her, and the girl fled.

"So you're together now?" Greg picked up the conversation again.

John grinned and felt himself blush a little. "Well..."

"Good for you." Greg seemed genuinely happy for them. "I just have one big question..."

"Oh yeah?" John said.

"Why isn't there any music?"

...

"Phew, it's been a long while since I danced this much!" Molly swept the sweat off her forehead as she flopped down in the chair next to John's, slightly out of breath. On the other side of the room, Greg was still staring open-mouthed at the spot where she had been waving her arms around and head-banging just a moment ago.

"Looks like you had a good time," John said, smiling.

"Oh yes, I did," Molly said cheerily. "I hadn't been on a lot of Hufflepuff parties before, you know, but so far everything they say about them seems right."

"Thanks," John said. "Though I hope not _everything_... In our fourth year there was this very persistent rumour about parties that would be happening in the baths. I didn't dare to wash for a week."

Molly giggled. "I bet that's not actually true. Sherlock would probably start complaining about hygiene and smell after three days."

"He would, wouldn't he?" John laughed and then saw that Sherlock was walking over in their direction, so he waved.

However, the tall boy only took a few steps more, stopping right in front of Irene Adler and actually leaning into her a little.

"Oh, who's she then?" Molly asked. "A friend of Sherlock's?"

"No," John snapped, although he didn't actually know if she was. It would be odd if he'd never told John about her. And yet Sherlock seemed to have known all about Irene's unusual occupation. What if he hadn't mentioned her because he was interested in her services and didn't think John would approve? What if he had made _use_ of them?

"Excuse me, please," John told Molly, and he strode over to Sherlock, making himself taller and broader than usual.

Somehow, in spite of the music and the people chatting around him, all he could hear were Sherlock and Irene's voices.

"So you'll show me," Sherlock was saying to her. "Tonight."

She laughed that infuriating laugh of hers. "Oh, _Mr Holmes_. Did you really think it'd be so easy? Those documents are my life. What do you think you've done to earn a look at them?"

"A look at _what_?" John asked, almost pushing over a second-year so he could stand next to Sherlock.

Irene smirked. "Oh, someone is jealous..."

"I have no reason to be," John bit at her. "Do I, Sherlock?"

He fiercely looked up at his boyfriend, whose eyes went wide when they took in his expression. "John..."

"I'd better give you two a moment, I think," Irene mocked. "But just to make it absolutely clear: the answer is no, Sherlock. And don't try to find me. I'll be tied up in a hidden room... Or rather, tying someone up."

"John," Sherlock complained when she'd left. "I'd almost gotten her to open up."

"Open up? Is that what you want her to do?" John snapped.

"What's gotten into you? Why are you all..." Sherlock gestured at John's form.

"I'm not anything." John's voice was almost a growl. "But you heard what Mary said about that girl."

"There's nothing wrong with what she does," Sherlock said, looking a little confused. "There is a demand and she supplies. As Mary said, that's clever."

"Clever, huh?" John said. "Isn't that the greatest good in your book? Got a little crush then?"

Sherlock's eyebrows knitted in puzzlement. Then he grabbed John's elbow and led him to the dormitories.

"What... Sherlock!" John protested, pulling his arm away.

"No. In here." Sherlock opened the door to John's dorm and closed it behind them. "Go on then."

"What am I supposed to do?" John asked, studying Sherlock for any sign of what the meaning was of all this. "Punch you?"

"Is _that_ what this made you want to do?" Sherlock enquired, looking vaguely amused.

"No..." What he wanted was to push Sherlock against the wall and... snog him, John decided. Because if he ended that sentence with where his thoughts actually went, things might turn too disturbing.

"You're jealous," Sherlock explained. "You want to claim me as yours. I'm letting you."

John blinked at him. And then he grabbed Sherlock by the lapels of his robe and smashed their lips together, pulling Sherlock closer, closer, his hands tangling in his hair and sliding over his face and down his shoulders and Sherlock was all _his_.

He felt infinitely better when they both came up for air.

Sherlock cleared his throat, looking a little winded. "Interesting," he commented.

John was just catching his breath, and slowly his brain was coming back online, replaying what had just happened. "Erm..." he muttered. "Sorry."

Sherlock smirked. "Oh no, it's fine... More than fine."

"I sort of... attacked you," John protested.

"Well... There's a market for that, too. Maybe you could start your own business."

John glared at him.

"However, John, I must admit I'd prefer if you don't," Sherlock continued. "My possessive streak may not go as far as yours, but to be fair I _would_ be disappointed if this grade of affection were to be shared with other people. At least for now."

"For now?" John growled. And then burst out in giggles because he'd realised how that sounded.

Sherlock joined in, looking almost triumphant. "I had no idea you were such a caveman."

"Oi," John said, still laughing. "Seriously though... What was all that about? What precious possession of Irene's did you want to see? Her whips?"

Sherlock snorted. "I doubt she'd refer to those as 'documents'. No, this is quite interesting, in fact. I think that, unknowingly, Mary put me on an interesting trail."

"Do you think those documents have anything to do with Moriarty?" John asked, his eyes widening.

"Well, perhaps not directly. As long as she won't show them to me, I can only speculate," Sherlock answered. "But remember what Mycroft said about the leader of that smuggling gang. She received information on businesses, but we know that Moriarty has a lot on Hogwarts, too. It didn't strike me before, but Irene _is_ in the perfect position to provide him with that."

John frowned. "It doesn't explain how he knew that you'd seen the message in the _Daily Prophet_ 's articles."

"True," Sherlock admitted, "but I doubt that he'd only have one person on his side, anyway. If Irene chooses to sell to him, I have no doubt that he has access to secrets that fit into a bigger picture."

John nodded. "Shame she doesn't want to talk to you."

"Oh, I'll think of something," Sherlock said, and he chuckled as John raised his eyebrows. "Something that doesn't involve her services. But John... I really should thank you. Throwing a birthday party wasn't as ridiculous an idea by far as I'd thought before. This could be a massive break-through."

John smirked. "Thanks. And while we're here..." He turned around and dove into the trunk at his bed end to pull out a wrapped parcel. "Happy birthday."

Sherlock took it and glanced at it. "A book, John? Really?"

"Well, I don't want a repeat of last year..." Admittedly, Sherlock had been fond of the Clabbert brain John had gotten him. So fond that he'd brought it to dinner one evening and had taken it out of the jar, putting it on the Hufflepuff table and poking it around, claiming he was studying it, while John had been trying to eat. From that point on he had resolved to be more careful in his choice of gifts for Sherlock.

Sherlock tore the wrapping paper from the book and then read its title. ' _Magical Murder and Misdemeanour - an account of 56 unsolved mysteries in the last 7 centuries._ '

"Oh," he said. "That's... That's actually..."

John snorted. "Are you surprised that I know you well enough to choose the perfect gift?"

" _Yes_ ," Sherlock answered, looking up with a very bright look in his eyes. "You _never_ stop surprising me."

John chuckled. "You're welcome."

...

By the time John was saying goodbye to their last non-Hufflepuff guests, Sherlock was curled up in one of the chairs with his new book.

"I thought you couldn't party because you wanted to work," John remarked as he perched on his armrest.

"This is ridiculous," Sherlock muttered in answer, gesturing at the book. "How could they not see that it was the wife? She poisoned his tea and vanished the body. The motive is clear, too. She wanted to elope with that mysterious letter-writer they suspected but never found. Who was a woman, by the way. I wonder if the murdering wife cared when she found out."

"Oh," John said. "That's only 55 unsolved mysteries now, then."

"54, actually," Sherlock said. "But the other six cases I've read so far were far more challenging. I'll need to gather more data to break through those."

"Good to hear it's not boring you just yet." John smiled. "But what about _our_ case?"

"Oh, I know what to do." Sherlock closed the book and put it on the table, then turned towards John. "I just figured I might as well kill the time reading. You see, Moriarty is probably a dead end. We'll need to focus on his associates to get to him. And Irene was _very_ eager to stress that she will be busy tonight, but considering what she'll be doing, I doubt she can take the documents with her. For all that it's 'her life', it may be quite easy to get a good look at them."

John frowned. "What are you planning?"

"Breaking into her dormitory," Sherlock said, grinning. "Oh, I know," he continued as John wanted to open his mouth, "she's not the only one sleeping there. But I'll think of something to clear the room."

"That's not actually your biggest issue," John said. "The girls' dormitories are protected against boys, you know. Loud alarms, sliding stairs... At least it's like that in the Gryffindor tower, but I'm sure the other dorms have security measures too."

Sherlock raised an eyebrow.

"I... I found out when I was seeing Sarah Sawyer," John mumbled, blushing. "In our fourth year. You know it wasn't... That I didn't..."

"Yes, alright." Sherlock smirked, apparently feeling that John had struggled long enough. "But really, John. In any other circumstance I'd be disappointed that you let yourself be stopped by such simple magic."

John frowned. "It's kind of hard to stop a staircase from turning into a slide while you're already standing on it, you know!"

"But the protection can be switched off," Sherlock said. "Obviously. Otherwise they'd be in a lot of trouble every time they accepted a student of non-binary gender, and I doubt Professor Bell would let that happen."

"Oh," John said. "I suppose... I hadn't thought of that."

"No, the hard part will be finding a distraction that is subtle enough not to raise any kind of suspicion, but striking enough to let them all come out. Unless I simply go for the Dungbomb approach..."

"Won't that girlfriend of hers, Kate, be suspicious anyway if she sees you?" John asked. "Maybe you should ask someone else to get them out of there. You could ask Mary, she'll probably help." He pointed at the blond girl who was one of the last Slytherins in the common room, peeling the last pancake from the plate that had been holding a four feet high stack.

"Excellent," Sherlock said, nodding. "You ask her – she'll react better to you than to me. And then we'll just have to wait until Irene is off to her nightly date."


End file.
